In the Romer Model, the Production Function , Where

In the Romer model, the production function , where A_t is knowledge and L_yt is the amount of labor in the output sector, exhibits:

A) constant returns to labor and increasing returns to labor and knowledge.
B) constant returns to labor and increasing returns to knowledge.
C) increasing returns to labor and constant returns to labor and knowledge.
D) decreasing returns to labor and constant returns to labor and knowledge.
E) increasing returns to labor and increasing returns to labor and knowledge.