A man covers half part of a certain distance at 25 km/ hr. He covers 40 percent of remaining distance at the speed of 8 km/hr and covers rest of the distance at the speed of 18 km/hr. What is his average speed for the entire journey?

A

(650/37) km/hr

B

(540/37) km/hr

C

(600/37) km/hr

D

(480/37) km/hr