Given below are two quantities named A and B. Based on the given information, you have to determine the relationship between the two quantities. You should use the given data and your knowledge of Mathematics to choose between the possible answers.

Quantity A: A man sitting in a car noticed that a bus is 200 meters ahead of him, after 63 seconds he noticed that the bus is 150 meters behind him. If the speed of the car is 78 km/h then find the speed of the bus.

Quantity B: 60 km/h