Concept:A factor divides a number exactly, leaving no remainder.
We check each option by dividing 3630.
Explanation:3630 ÷ 11 = 330 exactly → 11 is a factor.
3630 ÷ 3 = 1210 exactly → 3 is a factor.
3630 ÷ 5 = 726 exactly → 5 is a factor.
3630 ÷ 9 = 403.33 (not an integer) → 9 is not a factor.
Alternatively, sum of digits of 3630 is 3+6+3+0 = 12, which is divisible by 3 but not by 9. So 9 cannot divide 3630.
Answer:Option D (9) is not a factor.