Which best explains the children's fascination with Boo Radley?

In my opinion, the correct answer is B. His mystery feeds their imagination. The children have never even seen Boo, so they like to imagine and envision different spooky details about him. Jem fantasizes that he catches and eats squirrels and cats, which is why his hands are always bloody; he drools, his teeth are rotten, he has a dreadful scar on his face, etc.

He is queit and He is a mystery along with the rumors tha the twio have heard about and the fact that no every see hims.