Answer: d) 0 
Explanation:
 With the inequality given, y ≤ -1, solutions are -1 and all numbers less than -1. We will check all the options to see which is not a solution.
 a) -3 ✓
 -> This is not our answer. -3 is less than -1.
 b) -1 ✓
 -> This is not our answer. -1 is equal to -1.
 c) -6 ✓
 -> This is not our answer. -6 is less than -1.
 d) 0 ✗
 -> This is our answer! 0 is not less than -1.