Radio button
A round selector for picking exactly one option from a group.
A radio button is a small circle that becomes filled when chosen. Radio buttons live in groups; selecting one in the group automatically deselects the others. The metaphor comes from old radios where pressing one preset popped out the rest.
Use radio buttons when the user must pick exactly one of a few related options. For more than five or six options, switch to a dropdown so the screen does not get crowded.