Answer:
I'm ready to hit the sack
Explanation:
An idiom is when a phrase is used, but is not physically appropriate and not happening. Hitting the sack means to fall asleep, not actually hitting a sack :)
A. because it is just right
Answer:
B seems to make the most sense
Explanation:
All the other options seem like good reasons but are not as important as improving your overall skills (from my perspective at least). Hope this helps!