A 52-year-old man with a 3-year history of dilated cardiomyopathy presents with dyspnea on exertion, orthopnea, and peripheral edema. Echocardiography confirms heart failure with reduced ejection fraction (HFrEF, EF 28%). He is euvolemic after diuretic optimization and ACE inhibitor therapy. The cardiologist plans to initiate a β-blocker with proven mortality benefit in HFrEF. The structure marked **C** in the diagram represents agents with combined α and β-blocking activity. Which of the following β-blockers should be initiated at low dose and titrated every 2–4 weeks to target dose for mortality reduction in this patient?