List of top English Questions on Active and Passive Voice

Select the appropriate option to convert the following into active voice.
"Why was such a letter written by your brother?" 

Mark the correct Active Voice of the following:
"The wall is being built by the mason."

Choose the option which best expresses the same sentence in Passive Voice.
Somebody cleans the room every day.

Out of the four alternatives suggested, select the one which best expresses the following in Passive Voice: They are teasing you.