A patient with hyperparathyroidism is being evaluated for treatment options. Which of the following findings would most likely be present in this patient related to calcium metabolism?

Increased serum calcium levels due to excessive osteoclastic activity.

Decreased intestinal absorption of calcium due to low vitamin D levels.

Decreased renal calcium reabsorption leading to hypocalcemia.

Increased calcium excretion in urine due to low PTH levels.