An efficient reader always changes his rate according to his ______ and the difficulty of the reading material.

A．The differences between sheep and cattle breeding.
B．Living conditions in the colony of Massachusetts.
C．Food shortages in the early 1800s.
D．Livestock raising on early American farms.

A．Barry no longer lives in New York.
B．Barry doesn’t know how to economize.
C．The woman called Barry in California.
D．The woman didn’t ever meet Barry.