As per the given above sentence is given in Active Voice.
Circumstances obliged me to go.

Correct Option: C

As per the given above sentence is given in Active Voice.
Circumstances obliged me to go.
thus , required answer will be option C .

Use structure “subject + auxiliary + past participle + object”
As per the above sentence is given in Active Voice.
We had completed our task before sunset.

Correct Option: B

Use structure “subject + auxiliary + past participle + object”
As per the above sentence is given in Active Voice.
We had completed our task before sunset.
Hence , option B will be correct answer .

We can say that ,
The above given sentence is given in Passive Voice :-
Use structure “subject + auxiliary + past participle + by + object”
A massive tribal welfare programme has been launched by the government in Jharkhand.

Correct Option: D

We can say that ,
The above given sentence is given in Passive Voice :-
Use structure “subject + auxiliary + past participle + by + object”
A massive tribal welfare programme has been launched by the government in Jharkhand.
Hence , option D will be correct answer .

We can say that ,
The above given sentence is given in Passive Voice :-
Use structure “subject + auxiliary + past participle + by + object”
The entire block will be demolished by them.

Correct Option: C

We can say that ,
The above given sentence is given in Passive Voice :-
Use structure “subject + auxiliary + past participle + by + object”
The entire block will be demolished by them.
Therefore , required answer will be option C .

We can say that ,
The above given sentence is given in Passive Voice :-
Use structure “ auxiliary + subject + been + past participle”
Has your question been answered?

Correct Option: D

We can say that ,
The above given sentence is given in Passive Voice :-
Use structure “ auxiliary + subject + been + past participle”
Has your question been answered?
Therefore , option D will be correct answer .