The mass and the diameter of a planet are three times the respective values for the earth. The period of oscillation of a simple pendulum on the earth is 2 s. The period of oscillation of the same pendulum on the planet would be

• A. \(\frac{2}{{\sqrt 3 }}s\)
• B. \(\frac{3}{2}s\)
• C. \(2\sqrt 3 {\rm{\;}}s\)
• D. \(\frac{{\sqrt 3 }}{2}{\rm{\;}}s\)