年满2周岁的小儿的发育指标，下列那组属于正常体重 身高 头围 胸围

A．9kg 75cm 47cm 46cm

B．9kg 75cm 46cm 47cm

C．12kg 84cm 48cm 48cm

D．12kg 84cm 48cm 49cm

E．12kg 84cm 49cm 48cm

According to the T-Boat regulations the reason for providing adequate ventilation for a battery storage area is to prevent（）.

A.accumulation of carbon dioxide gas that chokes the battery

B.accumulation of explosive and toxic gases the battery can generate

C.mildew or dry rot in the battery box

D.battery failure including battery case meltdown caused by excessive heat