A 72-year-old man with moderate chronic obstructive pulmonary disease (FEV1 55% predicted) presents with increased breathlessness, purulent sputum and wheeze for 3 days. He has a low-grade fever (37.8 °C), respiratory rate 24 breaths/min, oxygen saturation 94% on room air and no signs of consolidation. He has had two exacerbations in the past year but none requiring hospitalisation. According to Therapeutic Guidelines and the 2023 primary care antibiotic summary, which oral antibiotic regimen is the most appropriate if antibiotics are indicated?