Final answer:
The bromination of 2,3-dimethylbutane is an example of a radical chain reaction, where a radical initiates the reaction and propagates through a series of steps to form the final product.
Step-by-step explanation:
The bromination of 2,3-dimethylbutane is an example of a radical chain reaction, which is answer A. In this reaction, the reaction begins with the initiation step, where a radical is formed. This radical then initiates the chain reaction by reacting with the 2,3-dimethylbutane to form a new radical. The reaction proceeds through propagation and termination steps to form the final product.