If the demand curve for open-heart surgery is vertical for people with serious heart conditions, then the demand for open-heart surgery is __ with respect to price.

If the demand curve for open-heart surgery is vertical for people with serious heart conditions, then the demand for open-heart surgery is __ with respect to price.
A.perfectly elastic
B.perfectly inelastic
C.inelastic
D.unit elastic
正确答案：perfectly inelastic