Ans: A
The area of the sector $OXY$
The area of the sector $OXY$
$\begin{array}{cl}
= & \pi (6)^2 \times \dfrac{60^\circ}{360^\circ} \\
= & 6\pi \text{ cm}^2
\end{array}$
Note that the area of the sector equals to the curved surface area the the cone. For the cone in answer A, the curved surface area
$\begin{array}{cl}
= & \pi (1)(6) \\
= & 6\pi \text{ cm}^2
\end{array}$
Therefore, the answer is A.
