______ of the parents has confirmed it was their child’s fault to be late for class, saying the school bus came later than usual.

A．Both

B．Either

C．None

D．Neither

小儿死亡率最高的年龄段是（）

A.围生期

B.新生儿期

C.婴儿期

D.幼儿期

E.幼童期