In the following questions, the sentences have been given in Active / Passive Voice. From the given alternatives, choose the one which best expresses the given sentence in Passive / Active Voice.

Someone saw him picking up a gun.

A. He was seen pick up a gun by someone

B. He was seen picking up a gun by someone

C. he was seen when he was picking up a gun

D. He was seen by someone pick a gun

Please do not use chat terms. Example: avoid using "grt" instead of "great".