A subset S ⊆ ℝ2 is said to be bounded if there is an M > 0 such that |x| ≤ M and |y| ≤ M for all (x, y) ∈ S. Which of the following subsets of ℝ2 is/are bounded?
1
{(x, y) ∈ ℝ2 : \(\rm e^{x^2}\) + y2 ≤ 4}
2
{(x, y) ∈ ℝ2 : x4 + y2 ≤ 4}
3
{(x, y) ∈ ℝ2 : |x| + |y| ≤ 4}
4
{(x, y) ∈ ℝ2 : \(\rm e^{x^3}\) + y2 ≤ 4}