A 34-year-old woman is diagnosed with her 3rd incidence of uncomplicated cystitis in the last 18 months. The trimethoprim–sulfamethoxazole resistance rate for E.coli is 10% in the community. Her last prescription filled was TMP/SMX and was completed 30 days ago. Which of the following would be the best choice treatment of an uncomplicated UTI for this patient?

A. Trimethoprim–sulfamethoxazole double strength, one tablet orally twice daily for 3 days
B. Amoxicillin 500 mg orally twice daily for 5 days
C. Fosfomycin 3 gm orally daily for 3 days
D. Ciprofloxacin 500 mg orally twice daily for 5 days