I do believe that it is C because the points fall above the value of y, and I do believe that the sign given here is supposed to be shown by a solid black line, meaning that points on the graph can be shown on the line.
1turn = 360 half a turn is 180360+180=540
You would multiply the weekly amount by the number of weeks (w) and add that to the one time fee:
t = 90w + 80
