PLZZZZZZZ HELP IM BEING TIMED!!!!!!!!!!!

Trapezoid ABCD has the following measurements, where AB is parallel to DC. AB = 19 mm, AD = 30 mm, DC = 34 mm, BC = 20 mm
What is the length of the median of the trapezoid?
A. 51.5 mm
B. 106 mm
C. 25 mm
D. 26.5 mm