Final answer:
Newborns delivered by clients addicted to narcotics most likely show symptoms of narcotic withdrawal typically within 24-72 hours after birth, as the newborn's body metabolizes and eliminates the narcotic substances.
Step-by-step explanation:
The symptoms of narcotic withdrawal in a newborn delivered by a client addicted to narcotics are most likely to be observed within 24-72 hours after birth (Option C). Immediate signs at birth are unlikely because the narcotic might still be present in the newborn's system. Symptoms typically emerge as the drugs are metabolized and eliminated from the baby's body. Within the first 12 hours, there may be some indications, but the full range of withdrawal symptoms generally becomes most evident after 24 hours and can peak within the first 72 hours post-birth.