A pendulum made of a uniform wire of cross sectional area A has time period T. When an additional mass M is added to its bob, the time period changes to TM. If the Young's modulus of the material of the wire is Y then 1Y is equal to: ( g= gravitational acceleration)

A. [(TM/T)²−1]Mg/A
B. [1−(TM/T)²]A/Mg
C. [1−(T/TM)²]A/Mg
D. [(TM/T)²−1]A/Mg