integrate : $\int \sec^3 x dx$

Question

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