The period of a simple pendulum whose bob is hollow metallic sphere is `T`. The period is `T_(1)` when the bob is filled with sand, `T_(2)` where it is filled with mercury and `T_(3)` when it is half filled with mercury Which of the following is true?
A. `T = T_(1) = T_(2)gtT_(3)`
B. `T_(1) = T_(1) = T_(3)gtT`
C. `Tgt TgtT_(1) = T_(2)`
D. `T = T_(1) = T_(2)ltT_(3)`