Answer:
B. Amount Donovan spends on granola bars each day.
Explanation:
B is the price of a granola bar, so 2B is the price of two granola bars. Donovan eats 2 granola bars each day, so if he buys them, he spends 2B per day on granola bars.
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Comment on the problem wording
Please be aware that the problem statement tells you only that he eats 2 granola bars each day. It does not tell you the relationship between Donovan's eating and Donvan's spending. The question asks about his spending, so there is insufficient information unless we make the assumption they are directly related.