The equation given is:
9x - 16 = 9x - 23
To find the number of solutions to this equation, we can simplify it by subtracting 9x from both sides to isolate the constants:
9x - 9x - 16 = 9x - 9x - 23
-16 = -23
After simplifying, we get -16 = -23, which is not a true statement. This means that the equation is inconsistent and has no solutions.
Therefore, the correct answer is:
C. 0