Q. A 65-year-old man presents to the emergency room with a three-day history of shortness of breath, fatigue, and swelling in his legs and ankles. He reports that these symptoms have been progressively worsening and that he has been feeling more tired than usual. He has a history of hypertension, which was diagnosed ten years ago, and has been managed with medication. The patient's vital signs on presentation are: blood pressure 150/90 mm Hg, pulse rate 90 beats/minute, and respiratory rate 22 breaths/minute. The physical examination reveals a patient with bilateral pitting edema and an S3 heart sound. Further evaluation reveals elevated levels of B-type natriuretic peptide (BNP) in the patient's blood. The patient is diagnosed with congestive heart failure, a complication of his hypertension. The patient is admitted to the hospital for further management and treatment with diuretics, ACE inhibitors, and beta blockers. He is also referred to a cardiologist for further evaluation and management. What is the signaling pathway of BNP?