A 50-year-old patient is admitted for acute coronary syndrome with a past medical history of hyperlipidemia and diabetes. The patient was transferred to the cardiac care unit for intubation because of worsening condition with increased shortness of breath. Physical examination and laboratory results reveal:
* BP: 140/90 mm Hg
* HR: 90 bpm
* RR:27 bpm
* O2 Sat: 90% on 2L
* Nasal cannula general: moderate distress
* Chest: bibasilar rales noted
* CV: S1, S2 present, + JVD 11 cm
* EXT. bilateral pulses, 2+ pitting edema, warm extremities
* BUN: 40 mg/dL
* Serum creatinine: 2.1 mg/dL
* Brain natriuretic peptide: 1120 pg/mL
Which of the following is the most appropriate first-line intravenous therapy for this patient?