He said, "The mice will play, when the cat is away."
A. He said that the mice will play when the cat is away.
B. He said that the mice would play when the cat was away.
C. He said that the mice would play when the cat would be away.
D. He said that the mice shall play, when the cat is away.
Answer: Option B

I think B is correct
Kindly check the answer its B
In passive voice we change will to would and is to was....
Option b is right???
IT MUST BE B.....IN INDIRECT "WILL" CHANGES TO "WOULD" AND "PRESENT SIMPLE" CHANGES TO "PAST SIMPLE".SO,B WOULD BE THE MOST SUITABLE OPTION.