The nurse is performing an admission assessment for a client with pyelonephritis who has urgency and burning while urinating. Which finding indicates an expected response when the nurse percusses the costovertebral angle?

A. Rigidity and firmness. This is not typically expected; rigidity and firmness may indicate muscle spasm or guarding. B. Sharp, severe pain. This is expected with pyelonephritis, as percussion over the inflamed kidney will elicit pain. C. Rebound tenderness. Rebound tenderness is more indicative of peritoneal irritation rather than pyelonephritis. D. Audible thud without pain. This is a normal finding; absence of pain does not align with the expected findings in pyelonephritis.