Correct Answer & Explanation
Option C
• The differences between consecutive terms should form an arithmetic progression with a common difference of 2:
5 + 7 = 12
12 + 9 = 21
21 + 11 = 32
32 + 13 = 45
45 + 15 = 60
• To maintain this series, the first term should be 5 instead of 6.
• Therefore, 6 is the wrong number.