Of the four options, only baths belong to a water system of an estate, so the correct answer is C.
Aviary is a birdcage, colonnades are supporting columns and wrestling grounds are areas used for wrestling.
It depends on which war you're referring to. I feel that the answer you're looking for is the radio, though.
The fall of the Berlin Wall in 1989, and the dissolution of the Soviet Union in 1991
