Although Capital Is a Variable Factor in the Long Run,once

Although capital is a variable factor in the long run,once chosen it becomes a fixed factor for a long time.A profit- maximizing firm must therefore select a method of production that is

A) adaptable to wide ranges of output over time.
B) economically efficient at current factor prices.
C) technologically advanced beyond methods currently used.
D) economically efficient at current factor prices and sufficiently flexible to adapt to changing factor prices over time.
E) labour intensive,as labour is always a variable factor.