Subject: mathqa
Question: one night a certain hotel rented 4 / 5 of its rooms , including 2 / 3 of their air conditioned rooms . if 3 / 5 of its rooms were air conditioned , what percent of the rooms that were not rented were air conditioned ?
Option: 
A: 70 %
B: 80 %
C: 90 %
D: 100 %
Answer: D