AMC 8 2011 Problem 2

Karl's rectangular vegetable garden is $20$ feet by $45$ feet, and Makenna's is $25$ feet by $40$ feet. Whose garden is larger in area? $\textbf{(A)}\ \text{Karl's garden is larger by 100 square feet.}$ $\textbf{(B)}\ \text{Karl's garden is larger by 25 square feet.}$ $\textbf{(C)}\ \text{The gardens are the same size.}$ $\textbf{(D)}\ \text{Makenna's garden is larger by 25 square feet.}$ $\textbf{(E)}\ \text{Makenna's garden is larger by 100 square feet.}$