Which of the following go through the midpoint of the side of a triangle?
A. an altitude
B. a perpendicular bisector of a side
C. a circumscribed circle
D. an angle bisector
E. a median
F. an inscribed circle
A. an altitude
B. a perpendicular bisector of a side
C. a circumscribed circle
D. an angle bisector
E. a median
F. an inscribed circle