He graph of the piecewise function f(x) is shown.

On a coordinate plane, a piecewise function has 2 lines. The first line has a closed circle at (1, 1) and goes down to an open circle at (3, negative 3). The second line has a closed circle at (3, negative 4) and continues horizontally to an open circle at (5, negative 4).

What is the domain of f(x)?
{x | 1 < x < 5}
{x | 1 < x < 5}
{y | −4 < y < 1}
{y | −4 < y < 1}