Sandra went to the grocery store with $25 to buy fruit. If she spent $12 on apples and $8 on bananas, which set of equations could be used to find the amount of money Sandra had left?
A. 25 - 12 = 13
13 + 8 = 21
B. 25 + 13 = 38
38 - 8 = y
C. 20 - 8 = y
y + 25 = 37
D. 12 + 8 = 20
25 - 20 = y