Okay, let's tackle this question about bronchopulmonary aspergillosis. The question is asking which statements are true. The options are a) eosinophil count >1x10^9/ml, b) associated with bronchial asthma, c) sputum positive for aspergillus antigen, d) increased IgG, and e) lower lobe predominance.

First, I need to recall what bronchopulmonary aspergillosis (BPA) is. BPA is a form of allergic bronchopulmonary aspergillosis (ABPA), which is an allergic reaction to Aspergillus species, typically in patients with asthma or cystic fibrosis. The key features include asthma exacerbations, sputum with eosinophils, and sometimes Charcot-Leyden crystals.

Looking at option a: Eosinophil count >1x10^9/ml. I remember that ABPA is characterized by elevated peripheral eosinophils, usually above 1000/µL (which is 1x10^9/L). So option a seems correct.

Option b: Commonly associated with bronchial asthma. Yes, ABPA is a complication of asthma, so this is correct.

Option c: Sputum positive to aspergillus antigen. ABPA patients often have Aspergillus in their sputum, either as hyphae or antigen. So option c should be correct.

Option d: Increased IgG. Wait, ABPA is associated with elevated IgE, not IgG. IgE is part of the allergic response. IgG might be more for other types of aspergillosis, like chronic or invasive forms. So option d is incorrect.

Option e: Lower lobe predominance. ABPA typically affects the upper lobes, not lower. Lower lobe involvement is more common in other conditions like tuberculosis or certain infections. So option e is incorrect.

Now, the correct options would be a, b, c. But looking at the options given in the question, the user is asking which of the options are true. The answer options for the user's question are A, B, C, D. Wait, the original question lists options a) to e), but the answer options here are labeled A. to D. Maybe the original question's options are a) to e), and the correct answer is a combination. However, the user's correct answer is given as "Correct Answer: . " but the options are A to D. Hmm, perhaps the user made a mistake in formatting. Wait, looking back, the user provided the options as a), b), c), d), e), but the answer options are A. B. C. D. Maybe the options are a to e, and the answer is a combination like ABCD or something else. But the correct answer given by the user is not specified here. Wait, the original question is presented as a multiple-choice question with options a to e, but the answer options are labeled A to D. That's confusing. Wait, maybe the user intended to list the options as A to E, but there's a formatting error. Alternatively, perhaps the options are a to e, and the answer is a combination of letters, but in the given structure, the user's correct answer is not filled in.

✓ Correct Answer: C. bcd