Given: If you visit Paris, then you will see the Eiffel Tower.
You did not see the Eiffel Tower.

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.

Really any number between them works. for example 144.951