Integrate : $\int \large\frac{1}{(4 \cos ^3 x -3 \cos x)^2}$$dx$

Question

\[\begin {array} {1 1} (a)\;\tan 3x+c \\ (b)\;\frac{1}{3} \tan 3x+c \\ (c)\;\frac{1}{3}\tan^2 3x+c \\ (d)\;None \end {array}\]