Q. A 39-year-old white woman is brought to the emergency room by her husband with complaints of progressively worsening headache, nausea, vomiting, lethargy and eventual obtundation. Patient’s husband says that she was previously in good health. Earlier during the day she had participated in a state marathon. The race started at 7:15 AM and she ran for 35 kilometers after which she had to be removed from the race due to overtime. She drank 30 glasses of water from drinking stations and her bottle during the run. Following the race, she developed headache and began to feel nauseated. She then asked her husband to call an ambulance and on the arrival of the ambulance, she was only responsive to pain stimuli. In the emergency department, her temperature is 37.2 °C (99.0 °F), blood pressure is 100/60 mmHg, pulse is 73 beats per minute and respiratory rate is 18 breaths per minute. Her medical history is significant for migraine. She does not use tobacco, alcohol or illicit drugs. Laboratory studies show the following results: Hemoglobin 9.9 g/dL Hematocrit 26.4% Sodium 122 mEq/L Potassium 3.9 mEq/L Chloride 95 mEq/L Which one of the following is the most appropriate fluid in the management of this patient?