If the rotation for this vessel is Felixstowe,Antwerp,Le Havre,Hamburg and Rotterdam.The container for Rotterdam is right at the（）of the heap.

A.uppermost

B.middle

C.bottom

D.aftermost

在诊室中为龋病敏感者涂氟防龋时，使 用的溶液是

A．0.2%NaF，8%～10%SnF₂或APF
B．2%NaF，8%～10%SnF₂或APF
C．2%NaF，2%～5%SnF₂或APF
D．2%NaF，2%～8%SnF₂及APF
E．2%NaF，10%～15%SnF₂及APF