— I wonder if I can board the plane with this return ticket.

— There _____ be no problem. Your ticket is valid until the end of this month. [ ]

A. must

B. shall

C. should

D. might

下列土中，______最适用于石灰稳定。

A．I_P=15～20的黏性土
B．含有一定黏性土的中粗粒土
C．I_p的级配砂砾、级配碎石
D．塑性指数在15以上的黏性土