Correct option is D
Option A: 7, 14, 21 → Multiples of 7 (7 × 1, 7 × 2, 7 × 3).
Option B: 8, 16, 24 → Multiples of 8 (8 × 1, 8 × 2, 8 × 3).
Option C: 9, 18, 27 → Multiples of 9 (9 × 1, 9 × 2, 9 × 3).
Option D: 6, 9, 18 → 6, 9, 18 are not all multiples of a single number in a proper sequence (6 × 1 = 6, 6 × 2 = 12, but here 9 appears instead of 12).
Thus, Option D does not follow the same multiplication sequence.