Step 1: Understanding the reaction.
The given reaction shows the oxidation of a benzene derivative using potassium permanganate (KMnO₄) under hot alkaline conditions. The compound is then reduced in the presence of hydrogen (H₂) over platinum (Pt), converting the molecule to the corresponding carboxylic acid. Step 2: Analyzing the options. (1) This option matches the expected structure after oxidation of the side chain and reduction to a carboxylic acid. (2) This is not correct as it represents a different ring structure. (3) This option shows a structure with a substituent at the wrong position. (4) This structure does not reflect the desired product from the reaction. Step 3: Conclusion.
The correct answer is (1) as it is the product after oxidation and reduction.