A good fuel should possess(a) high ignition temperature(b) moderate ignition temperature(c) high calorific value(d) both high calorific value and moderate ignition temperature

(d) both high calorific value and moderate ignition temperature

Explanation

The characteristics of a good fuel are the following.

1. It should have a high calorific value so that it can give us a sufficient amount of heat per unit mass.

2. It should have a proper ignition temperature so that it burns easily, this means that it should neither be too low nor too high. 

3. It should burn without giving out any harmful gases so that it does not pollute the air.

4. It should be inexpensive, easily available and easy to handle.