Final answer:
A nurse should alert the practitioner if contractions are every minute and last 120 seconds, as this may lead to fetal distress.
Step-by-step explanation:
The assessment that should alert the nurse to notify the practitioner is B. Contractions every minute that last for 120 seconds. This condition suggests that contractions are too frequent and abnormally long, which can lead to fetal distress due to the reduced oxygenated blood flow to the fetus during such prolonged contractions. Such abnormal contractions can be a reason for emergency birth interventions, such as a Caesarean section, to ensure the safety of the mother and baby