The formula for a cylinder's surface area is [tex]2\pi rh+2\pi { r }^{ 2 }[/tex] .
In this question h=x
Let's plug the values to solve.
[tex]2\cdot \pi \cdot 4\cdot 12+2\cdot \pi \cdot { 4 }^{ 2 }\\ 96\pi +32\pi =128\pi \quad square\quad units[/tex]
The answer is D
