Answer :
The reaction of CH3MgBr (methylmagnesium bromide) with carbon dioxide yields magnesium acetate, which upon acidic workup produces acetic acid.
option (B), Acetic acid, is the correct answer.
The reaction of grignard reagent CH3MgBr with carbon dioxide is a classic example of the formation of a carboxylic acid from a Grignard reagent. When CH3MgBr is treated with carbon dioxide, the product is a magnesium salt of the corresponding carboxylic acid, which upon protonation gives the carboxylic acid. Hence, the reaction of CH3MgBr (methylmagnesium bromide) with carbon dioxide will yield magnesium acetate, and upon acidic workup, it produces acetic acid (B). Therefore, the correct answer is B) Acetic acid.