The major product in the reaction

The major product of a reaction depends on the type of reagent and the conditions under which the reaction takes place. In this case, we are dealing with a bulky base. A bulky base tends to favor elimination reactions over substitution reactions due to its steric hindrance. This steric effect prevents the base from attacking the carbon directly attached to the leaving group, which is typical in substitution reactions.

Given that the base is bulky, it will likely abstract a proton from a carbon atom that is β to the leaving group. This leads to the formation of a double bond, resulting in an elimination reaction. Therefore, the major product will be the product of the elimination process rather than a substitution product. In this case, we are not expecting the formation of a substitution product, as the bulky base strongly disfavors that pathway.

The major product in this reaction will be the result of this elimination, where the bulky base facilitates the removal of a proton and the departure of the leaving group. The elimination will proceed via a mechanism such as E2, where the hydrogen and the leaving group are removed simultaneously, leading to the formation of the double bond. The major product will thus be the alkene formed after the elimination of the leaving group.

In summary, due to the presence of a bulky base, the reaction will predominantly lead to an elimination pathway. As a result, the major product in this reaction will be the product of elimination, not substitution.