An 11-year-old girl is brought to the clinic for progressive fatigue, muscle weakness, and a 3 kg weight loss over the past year. Her parents note she has had several episodes of vomiting, especially during minor illnesses, and seems to “crave” salty snacks. On examination, she has orthostatic hypotension and bronze-colored hyperpigmentation in her palmar creases and buccal mucosa. Which set of laboratory findings is most consistent with this presentation?