Correct option is B
Option (b) is the correct meaning of the given idiom.
Idiom: Hit the sack.
Meaning: To go to bed or go to sleep, especially after a long day.
Example: I’m exhausted. I think I’ll hit the sack early tonight.
Other related idioms:
· “Call it a night” – to stop working and go to bed.
· “Turn in” – to retire for the night.
· “Catch some Zs” – informal way to say sleep.