Tina is finding the quotient of. Is she correct? If not, what changes should be made?

For this case, we must find the quotient of
[tex](15x ^ 3 + 12x ^ 2-9x)[/tex] divided by[tex]3x[/tex], to verify if Tina was correct.
So:
[tex]\frac {15x ^ 3 + 12x ^ 2-9x} {3x} =\\\frac {15x ^ 3} {3x} + \frac {12x ^ 2} {3x} - \frac {9x} {3x} =\\5x ^ 2 + 4x-3[/tex]
So, Tina was wrong, she had to divide by 3x.
Answer:
Option B