A nurse is discussing a patient's lithium levels with another nurse. The laboratory findings show a lithium level of 0.6 mEq/L. Which statement made by one of the nurses best demonstrates an understanding of lithium levels?
A. The patient's plasma level is below the toxic level of 3 mEq/L and is considered therapeutic
B. The patient's plasma level exceeds 0.5 mEq/L and is therefore toxic
C. The patient's plasma level is between 0.4 and 1 mEq/L and is considered therapeutic
D. The patient's plasma level is below the 2.5 mEq/L level that would indicate toxicity