They will demolish the entire block.

The entire block is being demolished

The block may be demolished entirely

The entire block will have to be demolished by the boy

The entire block will be demolished

All of the above

The given sentence contains one of Model verb (Model Verb = will, shall, can, may, might, could, might, must, would). It is in active voice.

Rule :
Subject + Model verb + be + V3 + Optional Objects.