A fuel of cetane number 40 has the same ignition quality as a mixture of

A)
40% petrol and 60% diesel
B)
40% diesel and 60% petrol
C)
40% cetane and 60% alpha methyl napthalene
D)
40% alpha methyl napthalene and 60% cetane

Correct Answer : Option (C) :   40% cetane and 60% alpha methyl napthalene