A short chain is usually attached to the back of a petrol tanker and trailing behind it so that the?

A. petrol tanker is balanced on the road
B. heat generated by friction in the engine can be conducted to the earth
C. charges generated by friction in the tanker are conducted to the earth
D. tanker can move slowly as the chain touches the road surface
E. chain can produce sound in resonance with the noise from the tanker‘s engine

Correct Answer:

Option C – charges generated by friction in the tanker are conducted to the earth