Observation

(a)  Fuse is a safety device consisting of a strip of wire that melts and breaks an electric circuit if the current exceeds a safe level.

OR
Fuse is an electric safety device that can stop current from flowing if it exceeds rated value.

OR
Fuse according to IEE regulation is defined as device for opening a circuit by means of a conductor designed to melt when excessive current flows through.

(b)        Methods of Earthing

• Plate earthing
• Pipe earthing
• Rod earthing
• Strip or wire earthing                   
•       Reasons for the use of ELCB

• To reduce earthing impendence
• To prevent electric shock

The few candidates who attempted this question did poorly. This showed lack of understanding of the topic.