Concept:Grignard reagent reacts with alcohols (acidic hydrogen) to form an alkane.Explanation:2-Chlorobutane reacts with magnesium in dry ether to form a Grignard reagent.CH3−CH2−CH(Cl)−CH3Mg,dryetherCH3−CH2−CH(MgCl)−CH3This product is compound A (sec-butyl magnesium chloride).Ethanol has an acidic hydrogen on its hydroxyl group.The Grignard reagent abstracts this proton.The MgCl group is replaced by hydrogen, giving an alkane.CH3−CH2−CH(MgCl)−CH3+C2H5OH→CH3−CH2−CH2−CH3+Mg(OC2H5)ClThe alkane formed is butane (C4H10).Answer:Product B is butane, which corresponds to option B.