To solve the problem [tex]\(\frac{18 r^4 s^5 t^6}{-3 r^2 s t^3}\)[/tex], we need to follow these steps:
1. Divide the coefficients:
[tex]\[
\frac{18}{-3} = -6
\][/tex]
2. Subtract the exponents of [tex]\(r\)[/tex]:
[tex]\[
\frac{r^4}{r^2} = r^{4-2} = r^2
\][/tex]
3. Subtract the exponents of [tex]\(s\)[/tex]:
[tex]\[
\frac{s^5}{s^1} = s^{5-1} = s^4
\][/tex]
4. Subtract the exponents of [tex]\(t\)[/tex]:
[tex]\[
\frac{t^6}{t^3} = t^{6-3} = t^3
\][/tex]
Combining these results, we get:
[tex]\(
-6 r^2 s^4 t^3
\)[/tex]
Thus, the best answer is:
C. [tex]\(-6 r^2 s^4 t^3\)[/tex]