Radius of a circle is increasing uniformly at the rate of \[3cm/\sec .\]The rate of increasing of area when radius is \[10cm\], will be

• A.   \[\pi \,c{{m}^{2}}/s\]
• B.   \[2\pi \,c{{m}^{2}}/s\]
• C.   \[10\pi \,c{{m}^{2}}/s\]
• D.   None of these