Simplify the expression (3t²-2t+1) (2t) -t²) (6t-2) /(3t²) -2t+1)
a) 6t³ - 7t² + 4t - 2
b) 6t³ - 7t² + 4t - 1
c) 6t³ - 7t² + 5t - 1
d) 6t³ - 7t² + 5t - 2