The major product of the following reaction is

The correct answer is Option (4) → 

Core Concept - Friedel-Crafts Alkylation

This is an electrophilic aromatic substitution.

$OCH_3$ group is:

• Strongly activating
• Ortho/para directing due to +M (resonance donation)

Electophile formed: $CH_3^+$

So substitution occurs at ortho and para positions relative to $-\text{OCH}_3$.

Now check steric effect

Anisole undergoes Friedel-Crafts reaction, i.e., the alkyl and acyl groups are introduced at ortho and para positions by reaction with alkyl halide and acyl halide in the presence of anhydrous aluminium chloride (a Lewis acid) as catalyst.