【正确答案】 B

【答案解析】[分析] 是非题型。 根据第二段第四句Six of the nine were delivered by Caesarean section．推断B项正确。从第五句的意思And one baby, a twin, was born with a serious heart defect and a few days later developed life-threatening problems．可以排除A和D项。根据第二句的...the pregnancies themselves seemed to have proceeded according to plan可以排除C项。