Explanation:

To cover a distance of 800 kms using a 800 cc engine,

the amount of diesel required = 80 litres.

=the amount of diesel required to cover a distance of 1000 kms = 1000 x 80/800 = 100 litres

However, the vehicle uses a 1200 cc engine and it is given that the amount of diesel required varies directly as the engine capacity.

i.e., for instance, if the capacity of engine doubles,

the diesel requirement will double too.

Therefore, with a 1200 cc engine,

quantity of diesel required = 1200/800 x 100 = 150 litres.

Hence, option 2 is the correct answer.