To solve the reaction sequence provided, we need to identify each step and understand the transformations taking place.
The reaction starts with a benzoyl chloride. The first reagent, NaCN, is a cyanide ion source which will perform a nucleophilic substitution on the acyl chloride to form a nitrile. This leads to compound A, which is a benzoyl cyanide.
In the second step, \small \text{EtOH, H}_3\text{O}^+ indicates an acidic hydrolysis. This step converts the nitrile group to a carboxylic acid, yielding benzoic acid.
The third step involves the reaction of the resulting carboxylic acid with excess \small \text{MeMgBr} (methylmagnesium bromide), a Grignard reagent. In the presence of excess MeMgBr, the carboxylic acid first reacts to form a ketone intermediate, which can then further react with another equivalent of MeMgBr to form an alcohol after subsequent hydrolysis.
Hence, product B is a tertiary alcohol formed by the addition of two methyl groups to the benzene ring.
The correct structure of the major product involves the benzene ring with a tertiary alcohol group attached.
Therefore, the correct answer is the image with data-src-id "65d5eb8b0189fe50778ad757".
