Try multiplying the 1st and 3rd numbers in each row and comparing it to twice the middle number. Row 1: 5 × 8 = 40, and 2 × 20 = 40 — they match! Row 2: 4 × 3 = 12, and 2 × 6 = 12 — they match again. So the rule is: (1st number × 3rd number) = 2 × (middle number). Apply this to Row 3: 9 × ? = 2 × 27 = 54, so ? = 54 ÷ 9 = 6. The missing number is 6, option (1).