According to the "New" Theories of Economic Growth,increasing Marginal Returns

According to the "new" theories of economic growth,increasing marginal returns to capital investment is

A) possible,but only in the early stages of innovation before imitators rush in to drive prices down.
B) possible after initial fixed costs of innovation have been borne.
C) possible only if the capital is government-owned infrastructure.
D) impossible,and is thus a weak source of growth.
E) impossible because diminishing returns are unavoidable.