1. Mark an O on the picture you like, and mark an X on the picture you don't like.
2. Mark O on the picture you like, and mark X on the picture you don't like.
3. Check a circle on the picture you like, and check an X on the picture you don't like.
4. Check circle on the picture you like, and check X on the picture you don't like.
(Which sentences are grammatical? are all grammatical?)