Choose the correct parts of the compound nouns to complete the sentences.

Choose the correct option.

He asked a passer-[off|in|by|on] for help.

At Mary's birthday party, she was surrounded by a crowd of friends and hangers-[off|in|by|on].

The commander-[off|in|by|on]-chief decided to send troops overseas.

I'm so happy about my day [off|in|by|on]; I plan to catch up on some much-needed sleep.