To solve this problem, we will analyze each step of the reaction sequence.$\\$Step 1: Reduction of Acetaldehyde$\\$• The reaction starts with acetaldehyde $(CH_3CHO). \\$• It is reduced by $LiAlH_4$ to form ethanol $(CH_3CH_2OH). \\$• This is a standard reduction of an aldehyde to a primary alcohol.$\\$Step 2: Dehydration of Ethanol$\\$• Ethanol is then dehydrated using $H_2SO_4$ at high temperature.$\\$• This forms ethene $(CH_2=CH_2)$ through elimination of water.$\\$Step 3: Addition of HBr to Ethene$\\$• Ethene reacts with HBr to form bromoethane $(CH_3CH_2Br). \\$• This is an electrophilic addition reaction.$\\$Step 4: Wurtz Reaction$\\$• Bromoethane reacts with bromobenzene in the presence of $Na/dry\ ether. \\$• This is a Wurtz reaction, leading to the formation of ethylbenzene.$\\$The final product is ethylbenzene, which corresponds to Option 1.$\\$Therefore, the correct answer is Option 1.