A 67-year-old woman with a history of chronic obstructive pulmonary disease presents to the emergency department with a 2-day history of fever, productive cough with rust-colored sputum, and pleuritic chest pain. Her vital signs are as follows: • Temperature: 39.0°C (102.2°F) • Pulse: 110/min • Respiratory rate: 24/min • Blood pressure: 100/60 mm Hg A chest X-ray reveals a lobar consolidation in the right lower lobe. Blood cultures later grow gram-positive diplococci that display a mucoid colony morphology. In the context of microbial immune evasion, which virulence factor is primarily responsible for this pathogen’s resistance to opsonization and subsequent phagocytosis?