问题详情

In the standard (x,y) coordinate plane, a line segment has its endpoints at (3,6)and(9,4). What are the coor-dinates of the midpoint of the line segment？
A.(3,-1)
B.(3,1)
C.(6,2)
D.(6,5)
E.(12,10)请帮忙给出正确答案和分析，谢谢！