PP的理解问题

飞行2010

170.For any triangle T in the xy-coordinate plane, the center of T is defined to be the point whose x-coordinate is the average (arithmetic mean) of the x-coordinates of the vertices of T and whose y-coordinate is the average of the y-coordinates of the vertices of T.If a certain triangle has vertices at the points (0,0) and (6,0) and center at the point (3,2), what are the coordinates of the remaining vertex?

(A) (3,4)

(B) (3,6)

(C) (4,9)

(D) (6,4)

(E) (9,6)
这道题看得好乱啊，希望哪位牛人帮我分析一下。谢谢啦，大家虎年吉祥。

kingapple25

这题选什么？B么？