**(C) 5 : 8**

**From the question it is given that,**

Bus travels 160 km in 4 hours

Train travels 320 km in 5 hours

So, Bus travels a distance in one hour = 160/4 = 40 km/h

Train travels a distance in one hour = 320/5 = 64 km/h

Then the ratio of the distances travelled by them in one hour is = 40/64

Divide both numerator and denominator by 8.

= 5/8

**Therefore, the ratio of the distances travelled by them in one hour is 5: 8.**