Which of the following laboratory profiles is classically most consistent with an active, uncomplicated phase of Paget’s disease of bone (osteitis deformans)?

Explanation:
The correct option is c. Paget's disease is characterized by a focal, immense increase in bone turnover. In the active, uncomplicated phase, serum calcium and phosphorus levels are typically normal, while serum alkaline phosphatase (a marker of intense osteoblast activity compensating for rapid osteoclastic resorption) is markedly elevated. Reference: Campbell's Operative Orthopaedics, 14th Edition.