A simple pendulum is suspended inside a truck moving uniformly with a small acceleration of '3b'. Its mean position as an angle in radians with respect to the vertical is

Question

$\begin{array}{1 1}(a)\;0 \\(b)\;\frac{3b}{g} \\( c)\; 9.42 \\(d)\;None\;of\;the\;above \end{array}$