Using CSA of cylinder = $2\pi rh$:
$94.2 = 2 \times 3.14 \times r \times 5$
$r = \dfrac{94.2}{31.4} = 3$ cm
Answer: B) 3 cm
Substitute the CSA formula $2\pi rh = 94.2$, plug in $\pi = 3.14$ and $h = 5$, then solve for $r$. The denominator $2 \times 3.14 \times 5 = 31.4$, giving $r = 3$ cm exactly. Watch units and don't confuse CSA with TSA (which adds the two circular bases).