Related Clues:

• ___-in (like some mailing lists)
• Jukebox word
• Take sides
• Be choosy
• __-out clause
• Pick an alternative
• ___-out clause
• Settle on (with "for")
• Take one's pick
• Order from the menu, e.g.
• Don't sit on the fence
• Decide on, with 'for'
• Vote (for)
• Make one's decision
• Decide to take, with 'for'