The word "imperative" in the first paragraph most probably can be replaced by_________.

A．promoting policies that provide skills to employees
B．training more engineers, scientists and businessmen
C．expanding the pool of potential employees
D．providing education for all regardless of race or sex

A．has been nourished by fertilizers
B．contains vegetable matter that has not been consumed
C．has had chemicals and fertilizer added to it
D．contains large quantifies of vitamins