The distance on a map between a student’s house and her job is 4 centimeters. On the same map, the distance between her house and her school is 6 centimeters. The actual distance from her house to school is 9 kilometers. If d represents the approximate distance in kilometers between her house and her job, what is d?
A. 6 km
B. 9 km
C. 12 km
D. 18 km