Solve the equation. \[ \frac{x}{3}+9=\frac{x}{3} \] Select the correct choice below and, if necessary, fill in any answer box to complete your answer. A. The solution set is B. The solution set is $\{x \mid x$ is a real number $\}$. C. The solution set is $\varnothing$.

Step 1 ：The equation is \(\frac{x}{3}+9=\frac{x}{3}\).

Step 2 ：Subtract \(\frac{x}{3}\) from both sides to isolate the variable x.

Step 3 ：This gives us the equation 9=0, which is not possible.

Step 4 ：Therefore, there are no values of x that satisfy the equation.

Step 5 ：Final Answer: The correct choice is C. The solution set is \(\boxed{\varnothing}\).