A 60-year-old woman has 1-day history of nausea, vomiting, weakness, and confusion. Today, she has a difficulty walking and has fallen several times. She has been recently diagnosed with depression and started on fluoxetine 3 weeks ago. Her ER investigations reveal hyponatremia (Na 115mEq/L), low serum osmolality, urine sodium 90mEQ/L (Normal range 40-220mEQ/L), and inappropriately high urine osmolality. Which of the following is the most appropriate treatment?