'c" is the correct answer
We have
1/x ≤ x multiply both sides by x .....note that we're assuming that x ≠ 0
1 ≤ x2 subtract x2 from both sides
1- x2 ≤ 0 I like to turn the inequaliy into an equality and factor ....this gives us some "interval" points to work with!!
(1 - x) (1 + x) = 0 Then x = ± 1
Our answer comes from two of four intervals (-∞, -1], [-1, 0), (0, 1] or [1, ∞)
If you pick a point in each interval, you'll find that [-1, 0) and [1, ∞) are the intervals that "work' in the original inequality.......