S5. The author says that when a person persists in reflecting so as to ask the question how, he may at last become a

A．During early childhood.
B．In a person’s teens.
C．In a person’s twenties.
D．After a person turns fifty.

A．Prices are lower in downtown stores.
B．Job opportunities are better there.
C．Highway commuting has become unpleasant.
D．Environmental pollution is no longer a problem.