A nurse in a clinic is caring for a client who has heart failure and is taking digoxin. Which of the following statements by the client indicates the client is experiencing digoxin toxicity?

A. "My vision seems yellow." Visual disturbances (yellow or green halos, blurred or altered color vision) are classic signs of digoxin toxicity. B. "I am gaining weight." Weight gain suggests fluid retention/ worsening heart failure, not a specific sign of digoxin toxicity. C. "My tongue is red and beefy." A red, beefy tongue suggests nutritional deficiency (e.g., B₁₂/folate) or glossitis, not digoxin toxicity. D. "I am constipated." Constipation can occur with many medications or conditions but is not a hallmark of digoxin toxicity.