Final answer:
A diastolic blood pressure of 80 mm Hg or higher is diagnostic of hypertension, according to the American College of Cardiology and American Heart Association.
Step-by-step explanation:
A diastolic blood pressure that is diagnostic of hypertension is 80 mm Hg or higher according to the new guidelines from the American College of Cardiology and the American Heart Association. Hypertension is defined as chronic and persistent blood pressure measurements of 140/90 mm Hg or above for systolic and diastolic pressures, while pressures between 120/80 and 140/90 mm Hg are defined as prehypertension. Given the options, answer B, >/= 80 mm Hg, would be considered diagnostic of hypertension.