Final answer:
The finding that indicates a therapeutic effect of ceftriaxone in a client with bacterial pneumonia is improved oxygen saturation.
Step-by-step explanation:
The finding that indicates a therapeutic effect of ceftriaxone in a client with bacterial pneumonia is C. Improved oxygen saturation. Ceftriaxone is an antibiotic commonly used to treat bacterial infections, including pneumonia. When the medication is effective, it helps to improve the client's respiratory status by reducing the infection and inflammation in the lungs. Improved oxygen saturation means that more oxygen is being properly transported throughout the body, which indicates a positive response to the medication.