对“在正常情况下，胎头和脊柱是相称的。”英文表述正确的一项是（）。

对“在正常情况下，胎头和脊柱是相称的。”英文表述正确的一项是（）。
A.Fetal head is similar to vertebral column under normal condition.
B.Fetal head is proportional with vertebral column under normal condition.
C.Fetal head is proportional to vertebral column under normal condition.
D.Fetal head is similar with vertebral column under normal condition.
正确答案：Fetal head is proportional to vertebral column under normal condition.