Final answer:
The best response by the nurse is to inform the patient that she has prehypertension and suggest lifestyle changes to manage it.
Step-by-step explanation:
The best response by the nurse in this situation would be option 2: 'You have prehypertension; let's discuss your lifestyle.' A blood pressure reading of 126/84 mmHg falls within the prehypertension range, which is defined as blood pressure between 120/80 and 140/90 mmHg. Prehypertension is a stage where blood pressure is higher than normal, but not yet considered hypertension. Lifestyle changes, such as healthy eating, regular exercise, and stress management, can help manage prehypertension and prevent it from progressing to hypertension. Medication is not typically necessary at this stage.