Suresh and Dinesh travel a distance of 120 km such that the speed of Suresh is more than that of Dinesh. The sum of  their speeds is 75 km/h, and the total time taken by both is 6 hours and 40 minutes. The speed of Suresh is:

A

45 km/h

B

42 km/h

C

40 km/h

D

30 km/h