First ester reacts to form the ketone.  the ethyl ester is a alkyl ethanoate (we r not concerned abt alkyl part here) .RMgX reacts with  the alkyl ethanoate, first acetone is formed then aother equivalent of the grignard reagent acts to give the tertiary alcohol which is 1,1dimethyl ethanol

 

A) is the ans here.

 

to stop the reaction at this stage of ketone less reactive reagents like Gilman's reagent, R₂Cd , etc . can be used.