Mark had to travel 220 km in 4.5 hours, using a train that travels at the speed of 60 km/h or a bus that travels at the speed of 40 km/h, or any combination of the two modes of transport. For how lona did he travel by bus?

A

1 hour

B

1 hour 30 minutes

C

2 hours 30 minutes

D

2 hours