The simplest functions are the linear (or affine) functions --- the functions whose graphs are a straight line. They are important because many functions (the so-called differentiable functions) "locally" look like straight lines. ("locally" means that if we zoom in and look at the function at very powerful magnification it will look like a straight line.)

Enter the letter of the graph of the function which corresponds to each statement.

1. The graph of the line is increasing
2. The graph of the line is decreasing
3. The graph of the line is constant
4. The graph of the line is not the graph of a function

A	B	C	D