Which of the following would be expected to cause hyponatremia?

Correct Answer: D

Rationale: Excess ADH causes water retention, diluting plasma sodium and leading to hyponatremia.

Correct Answer: D

Rationale: Calcium is essential for bone structure, muscle function, clotting, and cardiac action potentials.

Correct Answer: D

Rationale: Calcitonin lowers blood calcium by inhibiting bone resorption.

Correct Answer: D

Rationale: Sweat loss reduces plasma volume, increasing osmolality.

Correct Answer: D

Rationale: NaCl does not buffer pH; it's an electrolyte, not a buffer.