A rational number is a number that can be written in the form:
Where p and q are coprimes. We are asked for finite sets, we can rule out options 3 and 4. In the set in option 2 the first element is:
This number cannot be written a ratio. We can rule out option 2.
All the elements in the set from option 1 can be written in the form p/q.Thus, the answer is the first option.