Answer:
It's actually: None of these.
Think about it: In this case we have an inequality, of x ≤ 0.
This basically means, that x can be less than OR equal to 0.
But 0 is neither negative or positive, so we can eliminate the following answer choices:
- all positive integers
- all negative real numbers
- all positive real numbers
- all negative integers
And we are left with "None of these"
Let me know if this helps!