Answer
Option A
Work Step by Step
Assume that the radius of the cylinder is $r$, and the height is $h$.
Find the volume of the rectangular prism: $18.5\times3.2\times5=296 cm^3$
Thus, $\pi r^2 h =296$
The surface area of the cylinder is given by: $2\pi r^2+2\pi rh\\=2\pi r^2+2r(\frac{296}{r^2})\\=2\pi r^2+\frac{592}{r}$
Differentiating the last expression, we get: $4\pi r-\frac{592}{r^2}$
Hence, $r=3.61$
