Which single factor is tended to have been considered by the author as the most important in the development of man

A．It would have a bad effect on the local people.
B．The local people do not want to sell any land.
C．The government doesn’t allow land to be sold.
D．There isn’t enough money available to buy land.

A．He helped construct a chapel.
B．He took over his family’s business.
C．He trained under Guggenheim.
D．He worked on a project overseas.