Best answer: A

Reasoning: In pre- and full-term infants a hemodynamically significant patent ductus arteriosus is classically associated with bounding peripheral pulses, and is linked to systemic “steal” complications such as necrotizing enterocolitis and pulmonary hemorrhage (Hamrick 2020 PMID 33093140; Hermes-DeSantis 2006 PMID 16625216). “CO₂ wash-out/CO wash out” is not a recognized clinical sign or complication of PDA, therefore it is the least likely option.