— Would you like _____ or shall we go by bus? 

— I prefer _____, but we have to take a taxi, for time is short. [ ]

A. walking; to walk

B. to walk; walking

C. walk; to walk

D. walk; walk

如图，边长L=20cm的正方形线框abcd共有10匝，靠着墙角放着，线框平面与地面的夹角α=30°．该区域有磁感应强度B=0.2T、水平向右的匀强磁场．现将cd边向右拉动，ab边经0.1s着地．在这个过程中线框中产生的感应电动势的大小与方向（　　）

A．0.8V方向：adcb

B．0.8V方向：abcd

C．0.4V方向：adcb

D．0.4V方向：abcd