They were flying kites. Change into passive voice

Question: They were flying kites. Change into passive voice--

A) Kites were flown by them.

B) Kites were being flown by them.

C) Kites were being flowing by them.

D) Kites was being flown by them.

Answer:
B) Kites were being flown by them.

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We don't like idle people. (passive)