If you get 210 utility points from consuming 3 Krystal burgers per week: A) and receive 250 utility points from consuming 4 Krystal burgers per week, the marginal benefit of the 4th burger was 40 utility points
B) and received 250-utility points from consuming 4 Krystal burgers per week, then the marginal benefit of consuming all 4 burgers must be 460 utility points.
C) and receive 250 utility points from consuming 4 Krystal burgers per week, the marginal benefit of the 4th burger must be higher than the 3rd burger
D) and receive 250 utility points from consuming 4 Krystal burgers per week, you should obviously keep eating more this week since it appears that the total benefit of eating them rises.