The Rationale for Developing a Model in Which Real GDP

The rationale for developing a model in which real GDP depends only on labor is

A) to prove that productivity growth was higher before the Industrial Revolution.
B) to prove that capital and technology play a key role in productivity growth.
C) to prove that productivity growth can occur without capital.
D) to prove that productivity growth can occur without technology.
E) to prove that labor is a key source of productivity growth.