The swimming pool . . . . . at 9 o’clock yesterday.

A. was repairing

B. was being repaired

C. was repaired

D. repaired

Answer: Option B

Solution(By Examveda Team)

Sentence is in past continuous tense in passive voice.
Rule :
Subject + was/were + being + V³ + other agents.
The swimming pool was being repaired at 9 o’clock yesterday.