Choose the grammatically correct sentence:

The correct answer is Option (1) → Is this seat taken, or can I sit here?

This and these, that and those:

• “This” goes with a singular noun and points to something near the speaker.
• “Seat” is singular, and “here” shows that it is near. So “this seat” is correct.

Why the Other Options are Incorrect?

Option 2: This shoes are too tight for me. — Incorrect. “Shoes” is plural, so it needs “these”, not “this”.
Corrected: These shoes are too tight for me.

Option 3: Those boy near the gate is my cousin. — Incorrect. “Boy” is singular, so it needs “that”, not “those”.
Corrected: That boy near the gate is my cousin.

Option 4: I enjoyed reading that books you lent me last week. — Incorrect. “Books” is plural, so it needs “those”, not “that”.
Corrected: I enjoyed reading those books you lent me last week.