Megan bought 3 pounds of apples that cost x dollars per pound. She gave the cashier a 20-dollar bill. Which equation could Megan use to find the amount of change, y, she should receive?
A. y = 20-3
O B. y = 20 - 3
) C. y = 20 x
D. y = 20 - 3x
Ey = 3x - 20