Iliana is correct since an integer means a whole number that is not a fraction, which includes negative AND positive numbers.
If s=4 than -s is negative (-4)
But if we plug in a negative integer, like -5, the negative signs are eliminated and it becomes positive, therefore Alonso is wrong (-s=-(-5)=5)
If the question was about a natural number Alonso would have been right since natural numbers are only from 0 and above