Choose the figure which is different from the other three.

The correct answer is Option (2) → 

Count the sides. Three figures have four sides each, though their shapes differ. Option (2), a right-angled triangle, has three sides, so it is the odd one out.

Option (1) — Incorrect. A rectangle: four sides, like two other figures.

Option (3) — Incorrect. A kite: four sides, like two other figures.

Option (4) — Incorrect. A rhombus: four sides, like two other figures.