The result was not the same as they had expected, ______ was rather disappointing. 

A．that

B．which

C．when

D．what

小儿各年龄分期，正确的是（）

A.围生期：生后脐带结扎至生后7天

B.新生儿期：生后脐带结扎至生后56天

C.婴儿期：生后至满2岁之前

D.幼儿期：1周岁以后到满3周岁之前

E.学龄前期：生后5岁至满7岁之前