Jack knows the surface area of a cylinder and its radius. He wants to find the cylinder's height. He needs to rewrite the formula a=2[tex] \pi [/tex] r (r+h) to find the cylinder's height (h) in terms of the cylinder’s surface area (A) and its radius (r). Which is the correct formula?

a) h = r + [tex] \frac{a}{2 \pi r} [/tex] 
b) h = [tex] \frac{a}{2 \pi r} [/tex]
c) h = [tex] \frac{a}{2 \pi r} - r^{2} [/tex]
d) h = [tex] \frac{a}{2 \pi r} - r[/tex]