A cylindrical tank with base area $$A=0.05\ \text{m}^2$$ is filled with water up to a height $$H=50\ \text{cm}$$. There is a small hole of area $$a=0.001\ \text{m}^2$$, with $$a\ll A$$, in the bottom of the tank. It takes time $$t$$ to empty the tank up to a height $$\frac{H}{2}$$, that is to empty half of the water volume. The additional time required to empty the tank completely is

A

$$t$$

B

$$t\sqrt2$$

C

$$t(\sqrt2-1)$$

D

$$t(\sqrt2+1)$$