15. Find the product of (5x – 3) and (x3 – 5x + 2).
a) 5x4 – 3x3 + 25x2 – 5x – 6
b) 5x3 – 28x2 + 25x – 6
c) 5x4 – 3x3 – 25x2 + 25x – 6
d) 5x3 + 22x2 – 5x – 6