One third of a journey is covered at the rate of 30 km/h, one fourth at the rate of 50 km/h and the rest at 60 km/h. Find the average speed for the whole journey. (Correct to 2 decimal places)

A

44.37 km/h

B

45.37 km/h

C

43.37 km/h

D

42.37 km/h