By dropping a stone in a quiet lake,a wave in the form of a circle is generated. The radius of the circular wave increases at the rate of $2.1 \text{ cm/sec}$. Then the rate of increase of the enclosed circular region,when the radius of the circular wave is $10 \text{ cm}$,is (Given $\pi = \frac{22}{7}$)

• A
  $66 \text{ cm}^2/\text{sec}$
• B
  $122 \text{ cm}^2/\text{sec}$
• C
  $132 \text{ cm}^2/\text{sec}$
• D
  $110 \text{ cm}^2/\text{sec}$