Test Preparation on Hydrocarbon-I-Chemistry Test Series IIT JEE-2020

Which is the best antiknock compound or Which one of the
following substances is used as an antiknock compound

In the commercial gasolines, the type of hydrocarbons which
are more desirable is

The reaction CH + Cl ¾¾¾__________CH3Cl + HCl uv light
4 2 is an example of