The time period of oscillation in sec of a simple pendulum of length l suspended inside a rocket moving vertically with an acceleration '2a' just above the earth is:

Question

$\begin{array}{1 1}(a)\;0\\(b)\;2 * \frac{\pi}{\frac{\sqrt{(2a+g)}}{I}} \\( c)\; 2 * \frac{\pi}{\frac{\sqrt{(g-a)}}{I}} \\(d)\;\frac{\sqrt{(2a+g)}}{I} \end{array}$