The reaction involves the addition of a Grignard reagent (CH₃MgBr) to an ester. Esters undergo nucleophilic acyl substitution with two equivalents of Grignard reagent. The first equivalent adds to the carbonyl, forming a ketone intermediate. The second equivalent adds to the ketone, ultimately yielding a tertiary alcohol.

The ester reactant is: $C{H}_{3}CH2C(=O)OC{H}_{2}C{H}_3$. After addition of two CH₃ groups, the final tertiary alcohol is $C{H}_{3}CH2C(C_{H}3{)}_{2}OH$.

Final Answer: The first option (top left image) is the correct major product.