A) I'm going to explain A to you and provide an image. The Sales are on the x-axis and the Total Fees are on the y-axis. You'll also see this in the table. The x-axis goes by multiples of 5 but only labels the multiples of 10. The y-axis goes by multiples of 0.5 but only labels whole numbers.
Now, to graph the relationship simply follow the numbers the table gives you. The first point would be straight on 4 on the y-axis, or total fees. So for $10 in sale, Alonso has a $4.50 fee. Because sales are on the x-axis, you'll go to ten where the graph labels sales. And because fees are on the y-axis, you'll go go up the 10 to the line between 4 and 5, so 4.5. And you repeat for the rest of the table.
B) The ratio y over x isn't constant because of the percentage. Alonso paying a $4 + a percentage of the sales doesn't create a constant ratio. 4.5 / 10 = 0.45 while 5 / 20 = 0.25. If the ratio y over x were constant, there wouldn't be different answers.
C) The relationship is proportional for two reasons. The first reason is that the graph is a linear graph. The second reason is 20% of the sales is added to the fee, which means every $10 is +$0.50 and every $29 is +$1. And because you add this percentage to $4, the fees and sales tax are going up at the same time and at the same rate.
Hopefully this helped and wasn't too confusing. :)