Time period of a simple pendulum, where L is length of the pendulum and g is acceleration due to gravity, is ______.

A

$$2 \pi \surd{\left(\frac{g}{L}\right)}$$

B

$$2 \pi \left(\frac{L}{g}\right)^2$$

C

$$2 \pi \left(\frac{g}{L}\right)^2$$

D

$$2 \pi \surd{\left(\frac{L}{g}\right)}$$