The lines with equations a x-2 y=c and 2 x+b y=-c are perpendicular and intersect at (1,-5). What is c ?

**Answer Choices**

A. -13

B. -8

C. 2

D. 8

E. 13

The lines with equations a x-2 y=c and 2 x+b y=-c are perpendicular and intersect at (1,-5). What is c ?

**Answer Choices**

A. -13

B. -8

C. 2

D. 8

E. 13