Which sentence contains a collective noun

Which choice is a major detail from paragraph two? a) the great wall is a large network of several walls and towers. b) the great wall looks like a long wall snaking its way across china. c) the great wall was constructed over hundreds of years beginning in 221 b.c. d) the great wall construction encouraged several independent kingdoms to unite.

Ihave no idea what the explanation is.

Using the ideas in these sentences the reader can most likely conclude that the father 1.enjoys surprising his wife with news. 2.is easily provoked into over-reacting 3.does not hold high regard for ojukwu. 3.does not respect his wife’s political views. :