A nurse in a mental health facility is collecting data from a client taking lithium. Which of the following information should the nurse report to the provider as an indication of lithium toxicity?

The correct answer is D: Slurred speech. Lithium toxicity can manifest as neurological symptoms such as slurred speech due to its effects on the central nervous system. A dry cough (A) is not typically associated with lithium toxicity. Elevated blood pressure (B) may be a sign of other conditions but is not specific to lithium toxicity. Stooped posture (C) is more indicative of musculoskeletal issues rather than lithium toxicity. In summary, slurred speech is a key neurological symptom of lithium toxicity, making it the correct choice in this scenario.