Billy Bob wants to gain some weight so that he can play football. Billy consumes only milk shakes and spinach. Milk shakes cost him $1 each and spinach costs $2 per serving. A milk shake has 850 calories and a serving of spinach has 200 calories. Billy Bob never spends more than $20 a day on food and he always consumes at least 8,000 calories per day. Which of the following is necessarily true?
A.
Billy Bob consumes at least 9 milk shakes a day.
B.
Billy Bob never consumes more than 6 servings of spinach a day.
C.
Billy Bob never consumes positive amounts of both goods.
D.
Billy Bob consumes only milk shakes.