OPTION C.
Step-by-step explanation:
The equation of the line in Slope-Intercept form is:
Where "m" is the slope of the line and "b" is the y-intercept.
In order to verify which fucntion is not linear, you can solve for "y" from each function. Then:
This is a Linear function.
This is a Linear function.
This is NOT a Linear function.
This is a Linear function.