Final answer:
The initial sign of aortic coarctation in a neonate is typically weak or absent femoral pulses, although other symptoms like difficulty breathing and poor feeding may also occur.
Step-by-step explanation:
The initial manifestation of aortic coarctation observed in a neonate is often weak or absent femoral pulses. Other symptoms that may be present in infants with this congenital condition include difficulty breathing, poor appetite, and failure to thrive. In cases where the condition is severe and restricts blood flow through the primary systemic artery, it becomes life-threatening and requires prompt surgical intervention for the best chance of survival. The correct option is d) Weak or absent femoral pulses.