Tsinghua University,       in 1911, is home to a great number of outstanding figures.

A．found

B．founding

C．founded

D．to be founded

若点P（1，1）为圆（x-3）²+y²=9的弦MN的中点，则弦MN所在直线方程为[ ]

A．2x+y-3=0

B．x-2y+1=0

C．x+2y-3=0

D．2x-y-1=0