Find the quotient of the quantity negative 12 times x to the 3rd power plus 21 times x to the 2nd power minus 6 times x all over negative 3 times x.
A.) −4x2 − 7x + 18
B.) 4x2 + 7x + 18
C.) −12x3 + 21x2 + 2
D.) 4x2 − 7x + 2