Integrate : $\int \tan x \tan 2x \tan 3x dx$

Question

$(a)\;\frac{1}{3}\log | \sec (3x)|-\frac{1}{2} \log | \sec 2x| - \log | \sec x | +c \\(b)\;\frac{4}{3}\log | \sec (3x)|-\frac{1}{2} \log | \sec 2x| - \log | \sec x | +c \\(c)\;\frac{1}{3}\log | \sec (3x)|+\frac{1}{2} \log | \sec 2x| - \log | \sec x | +c \\ (d)\;\frac{7}{3}\log | \sec (3x)|-\frac{1}{2} \log | \sec 2x| - \log | \sec x | +c$