A small hole of area of cross-section 2 ${\mathrm{mm}}^2$ present near the bottom of a fully filled open tank of height 2 m. Taking g = 10 $\mathrm{m}/{\mathrm{s}}^2$, the rate of flow of water through the open hole would be nearly

• A

  $6.4 \times {10}^{-6} {\mathrm{m}}^3/\mathrm{s}$

• B

  $12.6 \times {10}^{-6} {\mathrm{m}}^3/\mathrm{s}$

• C

  $8.9 \times {10}^{-6} {\mathrm{m}}^3/\mathrm{s}$

• D

  $2.23 \times {10}^{-6} {\mathrm{m}}^3/\mathrm{s}$