input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** An elderly man presents to his physician with complaints of difficulty breathing, easy fatigability, and bilateral leg swelling which began 2 months ago. His breathlessness worsens while walking, climbing the stairs, and lying flat on his back. He also finds it difficult to sleep well at night, as he often wakes up to catch his breath. His pulse is 98/min and blood pressure is 114/90 mm Hg. On examination, he has mild respiratory distress, distended neck veins, and bilateral pitting edema is evident on the lower third of his legs. His respiratory rate is 33/min, SpO2 is 93% in room air, and coarse crepitations are heard over the lung bases. On auscultation, the P2 component of his second heart sound is heard loudest at the second left intercostal space, and an S3 gallop rhythm is heard at the apex. Medication is prescribed for his symptoms which changes his cardiac physiology as depicted with the dashed line recorded post-medication. What is the mechanism of action of the prescribed medication?   (A) Decrease in transmembrane sodium gradient   (B) Preferential dilatation of capacitance vessels   (C) Inhibition of aldosterone-mediated sodium reabsorption   (D) Reduction in myocardial contractility
output: ['(A) Decrease in transmembrane sodium gradient <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Decrease in transmembrane sodium gradient  (B) Preferential dilatation of capacitance vessels  (C) Inhibition of aldosterone-mediated sodium reabsorption  (D) Reduction in myocardial contractility <> possible answers', '  An elderly man presents to his physician with complaints of difficulty breathing, easy fatigability, and bilateral leg swelling which began 2 months ago. His breathlessness worsens while walking, climbing the stairs, and lying flat on his back. He also finds it difficult to sleep well at night, as he often wakes up to catch his breath. His pulse is 98/min and blood pressure is 114/90 mm Hg. On examination, he has mild respiratory distress, distended neck veins, and bilateral pitting edema is evident on the lower third of his legs. His respiratory rate is 33/min, SpO2 is 93% in room air, and coarse crepitations are heard over the lung bases. On auscultation, the P2 component of his second heart sound is heard loudest at the second left intercostal space, and an S3 gallop rhythm is heard at the apex. Medication is prescribed for his symptoms which changes his cardiac physiology as depicted with the dashed line recorded post-medication. What is the mechanism of action of the prescribed medication? <> context']