What is the principal value in radians for \(cos^{-1}(-\frac{\sqrt{3}}{2})\) [inverse cosine of negative square root of 3 over 2]?

\(\mbox{W})-\frac{\pi}{6}\)

\(\mbox{X})-\frac{\pi}{3}\)

\(\mbox{Y})\frac{5\pi}{6}\)

\(\mbox{Z})\frac{11\pi}{6}\)
Y)\(\frac{5\pi}{6}\)