The average car decreases in value by about 15% per year. If a car's original value is $28,000, which function best represents its value, y, after t years? A. y=28,000(1+15)^t
B. y=28,000(1+0.15)^t
C. y=28,000(1-15)^t
D. y=28,000(1-0.15)^t​