You can eliminate B and C as they don't include the 5 different stores.
D is incorrect because it doesn't include the 7 items.
Therefore, A is correct because 7x is the 7 items multiplied by the average cost per item and you multiply by 5 because she does that at each of the 5 stores. It = to 50 because she started with $65 but ends up with $15 so you subtract $65 with $15 to get $50 as that's how much she spent.
