Answer:

opt

Answer	Crossword Clue
OPT	Go (for)
OPT	Make a choice
OPT	Make a pick

OPT	Elect (to)
OPT	Make a decision
OPT	...-out clause
OPT	Choose
OPT	Not dither
OPT	Be decisive
OPT	Elect
OPT	Check a box (for)

OPT	Go one way rather than another
OPT	... out (email list selection)
OPT	Pick
OPT	...-in clause
OPT	Make a selection
OPT	Decide (to)
OPT	Choose (to)
OPT	Vote (for)

OPT	Check the box (for)
OPT	Decide
OPT	Show a preference
OPT	Make up one's mind
OPT	Not req.
OPT	Take your pick
OPT	Select
OPT	Co-...

OPT	Cast one's vote
OPT	Get off the fence
OPT	Stop waffling
OPT	Go one way or the other
OPT	Check one
OPT	... out of (reject)