In His Model of Endogenous Technological Progress Based on Intentional

Multiple Choice

In his model of endogenous technological progress based on intentional, costly R&D activity, Paul Romer assumes that:

A) it becomes easier to create new products the more products have already been created.
B) it becomes harder to create new products the more products have already been created.
C) the marginal cost of creating new products is constant over time.
D) it eventually becomes so expensive to create new products that economic growth ceases altogether.