A linear function is shown on the graph.

a linear function beginning with closed circle at 0 comma 2 and ending with a closed circle at 4 comma 6

What is the domain of the function?

{x | 0 ≤ x ≤ 4}
{x | 0 < x < 4}
{y | 2 ≤ y ≤ 6}
{y | 2 < y < 6}