Single Selection Radio Buttons 
To add a Single-Selection Radio Button field to the User Profile form, click on the following to your left: User Profile Fields> Add New User Profile Field then select Single-Selection Radio Buttons from the dropdown menu.

The Single-Selection Radio Buttons form allows you to add a custom single-selection radio button field to the User Profile form.
You must click Save for changes to take effect.
Add New User Profile FieldOptional Input

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User Contributed Notes: Single Selection Radio Buttons