A rectangular region is bounded by the graphs of the equations y=a, y=-b, x=-c, and x=d, where a, b, c, and d are all positive numbers. Which of the following represents the area of this region?

**Answer Choices**

A. a c+a d+b c+b d

B. a c-a d+b c-b d

C. a c+a d-b c-b d

D. -a c-a d+b c+b d

E. a c-a d-b c+b d