In an ac circuit, the current is given by  $\mathrm{i}=5\sin \mathrm{\hspace{0.17em}}\left(100\mathrm{\hspace{0.17em}}\mathrm{t}-\frac{\mathrm{\pi }}{2}\right)$ and the ac potential is $\mathrm{V}=200\sin \left(100\right)\mathrm{volt}.$ Then the power consumption is 

• A

  20 watts

• B

  40 watts

• C

  1000 watts

• D

  0 watt