Could someone help with this problem?

Determine which of the following posets (S, <=) are lattices.

1. A = {1, 3, 6, 9, 12} and <= is the divisibility relation.

2. B = {1, 2, 3, 4, 5} and <= is the divisibility relation.

3. C = {1, 5, 25, 100} and <= is the divisibility relation.

4. Both 1 and 3

My answer: 3

Is this right? I think it is but I'm not 100% sure.