Final answer:
A client at risk for a hypertensive emergency is one who abruptly stops taking antihypertensive medication, as this leads to a dangerous spike in blood pressure. so, option C is the correct answer.
Step-by-step explanation:
A client who is at risk for developing a hypertensive emergency is C) A client who abruptly stops taking antihypertensive medication. Such a sudden discontinuation can lead to a rapid increase in blood pressure, potentially causing a life-threatening hypertensive crisis. On the other hand, a client with well-controlled hypertension on medication, isolated systolic hypertension, or white coat hypertension would generally not be at immediate risk for a hypertensive emergency unless there were additional complicating factors.
It's important for patients with hypertension to continue their medication as prescribed and not to stop suddenly without consulting a healthcare provider. Hypertensive emergencies can lead to severe complications such as stroke, heart attack, and kidney failure. Compliance with medication and lifestyle changes are key to managing high blood pressure.