I have a Barbarian that wants to do the Path of the Giant, I attempted to make the homebrew because the one another member made had issues with the option selection in the third level. 

"You learn to speak, read, and write Giant (or one other language if you already know it). You also learn either the druidcraft or thaumaturgy cantrip (your choice). Wisdom is your spellcasting ability for this spell." But the option part of the tab in character building is blank...

Any help is appreciated!

I attempted to make the homebrew

Help with homebrew should be requested in the Homebrew & House Rules Forum (link: https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules). There are pinned threads with guides and tutorials on homebrewing there and those that frequent that forum are more likely to assist you correctly.

because the one another member made had issues with the option selection in the third level. 

Ensure they have access to the Glory of the Giants book. If this is via content sharing the character must be created/edited while inside the campaign that has content sharing enabled. If they have purchased the book they may need to ensure their entitlements are in sync by going to Account > Licenses (or click here: https://www.dndbeyond.com/account/licenses). They should also ensure they're using the correct Barbarian: there's 2 versions of all core classes, a 2014 version and a 2024 version. If the subclass is intended for the 2024 version they need to use the 2024 Barbarian. They should also ensure the relevant toggles are enabled in the Home tab of the character builder: 2014 or 2024, as appropriate, and the Expanded Rules one.

If you have the book and are the DM of the campaign they are in, you can access the sheet yourself and select it for them. They'll be able to retain access even while levelling up, as long as they don't change the subclass to anything else.

 "You learn to speak, read, and write Giant (or one other language if you already know it). You also learn either the druidcraft or thaumaturgy cantrip (your choice). Wisdom is your spellcasting ability for this spell." 

Add Class Feature

Fill name with the name of this feature.

Snippet: "You learn to speak, read, and write Giant (or one other language if you already know it). You also learn either the druidcraft or thaumaturgy cantrip (your choice). Wisdom is your spellcasting ability for this spell."

Description: "You learn to speak, read, and write Giant (or one other language if you already know it). You also learn either the druidcraft or thaumaturgy cantrip (your choice). Wisdom is your spellcasting ability for this spell."

Required Class Level: 3
Display Order: 1
Check Has Options box
Class Levels Where Options Known: 3
Feature Type: Granted
Click Create Feature

Next to Class Feature Options click Add An Option
Name: Giant
Snippet: "You learn to speak, read, and write Giant"
Description: "You learn to speak, read, and write Giant"
Click Create Option

Next to Modifiers click Add Modifier
Modifier Type: Language
Modifier Sub-Type: Giant
Click Save

Click Save Changes

Click Cancel

Next to Class Feature Options click Add An Option
Name: Other (Giant Already Known)
Snippet: "You learn to speak, read, and write one language of your choice."
Description: "You learn to speak, read, and write one language of your choice."
Click Create Option

Next to Modifiers click Add Modifier
Modifier Type: Language
Modifier Sub-Type: Choose A Language
Click Save

Click Save Changes

Click Cancel

Click Save Changes

Next to Spells click Add A Spell

In the Spell Box add in Druidcraft and then add Thaumaturgy.
Ability Score: Wis
Leave everything else as is and click Save

Click Save Changes

Click Cancel

Click Save Changes

You are done.

For the character, ensure Homebrew is enabled in the Home tab of the character builder and select your homebrew subclass. The feature will appear and allow the option selection.

Click spoiler below for screenshots of the results.

Quote from spamandtuna >>

The language is probably being handled by a Modifier instead. The spells are surely being added under Spells.

I don't see a reason you'd need to use Options here.

 
While the language can be handled with a single modifier "choose" - it is more intuitive and user-friendly to present an option: one for the default Giant and another for "Other" if Giant already known.