A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of

A)
75% petrol and 25% diesel
B)
75% iso-octane and 25% normal heptane
C)
75% diesel and 25% petrol
D)
75% normal heptane and 25% iso-octane

Correct Answer : Option (B) :   75% iso-octane and 25% normal heptane