$A$ vessel completely filled with water has holes $A$ and $B$ at depths $h$ and $3h$ from the top respectively. The hole $A$ is a square of side $L$ and $B$ is a circle of radius $r$. The water flowing out per second from both the holes is same. Then $L$ is equal to

• A
  $r^{\frac{1}{2}}(\pi)^{\frac{1}{2}}(3)^{\frac{1}{2}}$
• B
  $r(\pi)^{\frac{1}{4}}(3)^{\frac{1}{4}}$
• C
  $r(\pi)^{\frac{1}{2}}(3)^{\frac{1}{4}}$
• D
  $r^{\frac{1}{2}}(\pi)^{\frac{1}{3}}(3)^{\frac{1}{2}}$