A first-grade teacher use ten flash cards, numbered 1 through 10, to teach her students to order numbers correctly. She has students choose four flash cards randomly, then arrange the cards in ascending order. One day, she removes the cards numbered "2" and "4" from the deck of flash cards. On that day, how many different correct arrangements of four randomly selected cards are possible ？（）

A.70

B.210

C.336

D.840

E.1，680

下列哪项不是单纯室间隔缺损修补术的手术入路（）

A.肺动脉入路

B.右心房入路

C.主动脉入路

D.右心室入路

E.左心室入路