The nurse is monitoring several older adults for adverse drug effects. Which client requires closest monitoring for drug toxicity?

A. A client who consumes a high-carbohydrate, low-protein diet.
B.A client who consumes a high-carbohydrate, low-protein diet is at highest risk of drug toxicity because an unbound active drug still circulates in the bloodstream.
C. client with a decreased, not an increased, hemoglobin and plasma protein level, is at higher risk of drug toxicity.
D. client who refuses to take antihypertensive medication would have a low drug level and would be less likely to experience drug toxicity.