Answer:
C. After a hard day's work, I needed a break, so I took the night off.
Explanation:
a) After a hard day's work. I needed a break, so I took the night off.
(change first period to a commma)
B. After a hard day's work, I needed a break so I took the night off.
(change to I needed a break after a hard day's work, so I took the night off.)
C. After a hard day's work, I needed a break, so I took the night off. (CORRECT)
D. After a hard day's work, I needed a break so I took the night off.
(same as question b)