Looking at the four numbers, I need to identify what makes one different from the others.
Let me check the sum of digits for each number:
For 3085: 3+0+8+5=16
For 9900: 9+9+0+0=18
For 5116: 5+1+1+6=13
For 8179: 8+1+7+9=25
A number is divisible by 9 if and only if the sum of its digits is divisible by 9.
Checking each sum:
- 16 is not divisible by 9
- 18 is divisible by 9
- 13 is not divisible by 9
- 25 is not divisible by 9
9900 is the only number divisible by 9.
Therefore, the different one is Option 2.