At last nights party Larry said something that I though was beyond me. The underlined part

At last nights party Larry said something that I though was beyond me. The underlined part means______.(2013-68)

A．I was unable to do

B．I couldn"t understand

C．I was unable to stop

D．I couldn"t tolerate

请帮忙给出正确答案和分析，谢谢！