A simple pendulum has a bob of mass m and a light string of length l. The string is replaced by a uniform rod of mass m and of the same length l. The time period of this pendulum is

A

$$2\pi\left(\frac{l}{g}\right)^{1/2}$$

B

$$2\pi\left(\frac{8l}{9g}\right)^{1/2}$$

C

$$2\pi\left(\frac{9l}{8g}\right)^{1/2}$$

D

$$2\pi\left(\frac{2l}{3g}\right)^{1/2}$$