The answer to a boolean question is stored as the boolean
A boolean question may take any of the styles of the select question; it defaults to displaying as buttons.
The boolean question only has two choices, "Yes" and "No".
If you'd like to change the labels of those choices, you can do so in the choices tab.
If you'd like to have more than two choices mapped to true or false, use a select question and change Choice value type to boolean.