Use a Calculator to Evaluate $\cos ^ { - 1 } ( - 0.81 )$

Multiple Choice

Use a calculator to evaluate $\cos ^ { - 1 } ( - 0.81 )$ .Round your answer to two decimal places.

A) 0.68
B) $- 0.89$
C) 0.72
D) $- 0.94$
E) 2.51