Seema and Geeta start at the same time to ride from place A to place B, which is 90 km away from A. Seema travels 3 km per hour slower than Geeta. Geeta reaches place B and at once turns back, meeting Seema 15 km from place B. Geeta's speed (in km/h) is:

A

12

B

10.5

C

7.5

D

9