The man lived in a dilapidated house made of mud and bricks.

crumbling
old
thatched
crashing

The correct answer is A. crumbling.

A dilapidated house is one that is in a state of disrepair and is likely to collapse. The word “crumbling” means to fall apart or break into small pieces. This is the best description of the house in the question, as it is made of mud and bricks and is likely to fall apart.

The other options are not as accurate descriptions of the house. The word “old” does not necessarily mean that the house is in a state of disrepair. The word “thatched” means that the roof of the house is made of straw or reeds. The word “crashing” does not make sense in the context of the question.

In conclusion, the correct answer is A. crumbling.