Which scenario is most likely the one shown on the graph?
a. the total amount of money in the cash register, y, containing $50 in change and small bills and x $100 bills
b. the total number of puzzle pieces, y, in a brand new 50-piece puzzle, and x brand-new 100-piece puzzles
c. the total weight of the barbell, y, where the bar weighs 50 pounds and x 100-pound weights are added to it
d. the total number of calories, y, in a salad with vegetables containing 50 calories topped with x ounces of salad dressing at 100 calories per ounce