Note :- Rule to make active voice of Past Perfect Tense :
Passive subject + had + been + third form of verb + by + passive object
2. Did he buy a car ?
Was a car bought by him.
Did car bought by him.
Did a car bought by him.
Were a car bought by him.
Answer: Option A
3. It is time to do our business.
It is time for our business to be done.
It is time to our business to be done.
It is time our business to be done.
It is time for our business be done.
Answer: Option A
Explanation:
Note: Please note the use of "for"
4. Someone has stolen his book.
His book is been stolen.
His book has been stolen.
His book is stolen.
His book has stolen.
Answer: Option B
Explanation:
Apart from Rule to make active voice of Present Perfect Tense, which is
Passive subject + has/have + been + third form of verb + by + passive object
Please also note that words like, "someone", "somebody", "people", "police", "public" etc are dropped. But in rare cases we can use them if sentence meaning is not clear.