y = 4x+7 is in the form y = mx+b, which is slope intercept form. All non-vertical lines can be written in this form
m = 4 is the slope
b = 7 is the y intercept
This equation is linear since it can be written in slope intercept form. The graph is a straight line. It cannot be nonlinear as that would contradict it being linear. It's either one or the other (either linear or nonlinear). It cannot be both. It cannot be neither.
Answer: Choice A) Linear
