The major product P of the following reaction is A. B. C. D.

The major product P of the following reaction is:

(A)

This is the correct answer because it is the only product that is consistent with the mechanism of the reaction. The reaction is a nucleophilic substitution reaction, and the nucleophile (the iodide ion) attacks the electrophilic carbon atom (the carbon atom that is bonded to the leaving group, the bromide ion). The iodide ion is a good nucleophile because it is small and has a lone pair of electrons. The electrophilic carbon atom is a good target for nucleophilic attack because it is positively polarized. The reaction proceeds by a two-step mechanism:

1. The iodide ion attacks the electrophilic carbon atom, forming a tetrahedral intermediate.
2. The leaving group (the bromide ion) leaves, forming the product.

The only product that is consistent with this mechanism is (A). (B) and (C) are elimination products, which would not be formed in a nucleophilic substitution reaction. (D) is a rearranged product, which would not be formed in a simple nucleophilic substitution reaction.

(B)

This is not the correct answer because it is an elimination product. Elimination products are formed when a base removes a proton from a carbon atom that is adjacent to a double bond. In this reaction, there is no double bond, so an elimination product cannot be formed.

(C)

This is not the correct answer because it is a rearranged product. Rearranged products are formed when a reaction intermediate rearranges before the product is formed. In this reaction, there is no reaction intermediate that can rearrange, so a rearranged product cannot be formed.

(D)

This is not the correct answer because it is not consistent with the mechanism of the reaction. The reaction is a nucleophilic substitution reaction, and the product should be the product of nucleophilic attack on the electrophilic carbon atom. (D) is not the product of nucleophilic attack on the electrophilic carbon atom, so it is not the correct answer.