Since it is a Trapezoid:
TR is Parallel to PA
For a Parallel lines the sum of the 2 opposite interior angles add up to 180
Therefore:
x + (3x + 16) = 180
x + 3x + 16 = 180
4x + 16 = 180
4x = 180 - 16
4x = 164
x = 164/4
x = 41
x = 41 degrees. Option C.
