The formula for inverse hyperbolic cosine is:
\[
\cosh^{-1} x = \log \left( x + \sqrt{x^2 - 1} \right)
\]
Substituting \( x = 2 \):
\[
\cosh^{-1} 2 = \log \left( 2 + \sqrt{2^2 - 1} \right)
\]
\[
= \log (2 + \sqrt{4 - 1}) = \log (2 + \sqrt{3})
\]
Thus, the correct answer is \( \log(2 + \sqrt{3}) \).