The Correct answer is C.

Explanation

To evaluate the expression?, it is necessary to determine the values of??and. Since the sum of the measures of the angles of any triangle is??degrees, and a right angle has measure??degrees, the value of??can be found by solving the equation?. This yields?. The value of??can be found by solving the equation?. This yields?. Finally, the values for?and??are substituted into the expression??to obtain?