Potential Mistake in CFAI Practice Exam

I don’t understand how the answer could be what they are saying, here it is, #33 of the morning session.

Demand for a good is most likely to be elastic when:

a) the good is a necessity

b) a lesser proportion of income is spent on the good

c) the adjustment to a price change takes a long time

How could C be the answer? I always thought if demand takes a long time to adjust, then it is inelastic!!!