The integral of \(\sec x\) is a standard result:
\[
\int \sec x \, dx = \log \left| \sec x + \tan x \right| + c.
\]
To verify, use the fact that:
\[
\frac{d}{dx} \left( \log \left| \sec x + \tan x \right| \right) = \sec x.
\]
Thus, the correct answer is \( (A) \).