Select the option that expresses the given sentence in passive voice.
The maid was dusting the hall when the door-bell rang.

A

The door-bell rang when the hall was being dusted by the maid.

B

The door-bell rang by the maid when the hall was dusted.

C

The door-bell rang when the maid was dusting the hall.

D

The door-bell rang when the maid is dusting the hall.