**Concept: The question tests on the area of Counting**

**Solution:**

Rearranging, we get

x−18=3√x

Squaring both sides, x2−36x+324=9x

Rearranging, x^2−45x+324=0

x^2−36x−9x+324=0

=>x^2−36x−9x+324=0

x(x - 36) - 9(x - 36) = 0

(x - 36) (x - 9) =0

The solutions are 36 and 9 and the factors are 1,2,3,4,6,9,12,18 and 36.

8 is not a factor of the solutions.**Option D**