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Step 1: Nucleophilic Substitution with aqueous KOH

The starting material contains two bromine atoms: an unreactive aryl bromide on the benzene ring and a reactive terminal alkyl bromide. Aqueous KOH selectively undergoes an $S_N2$ reaction with the terminal alkyl bromide to replace the $-Br$ group with a hydroxyl group ($-OH$), forming a primary alcohol side chain.

Step 2: Oxidation (Jones Oxidation)

Chromium trioxide in an acidic medium is a strong oxidizing agent. It oxidizes the newly formed primary alcohol side chain fully into a carboxylic acid group -COOH.

Step 3: Intramolecular Friedel-Crafts Acylation with H2SO4 with Heating 

Concentrated sulfuric acid and heat dehydrate the carboxylic acid side chain, generating an electrophilic acylium ion intermediate. This ion undergoes an intramolecular Friedel-Crafts acylation by attacking the benzene ring at the available position ortho to the side chain.