Is there meant to be a picture attached with this?
The y-intercept is being changed. In the equations given we are using the formula (y=mx +b), b means the y intercept. In this we are changing the y intercept from 2 to -1. There is nothing else being changed.
I don't think all of the answer choices are here since they are all the same except for 4. However, the best statement to describe a polygon is that it is a closed plane figure with three or more sides that are straight. The correct answer is A.