mrcem2-1100

A 25-year-old woman comes to the clinic with a swollen and red right knee. She recently returned from a trip to Bangkok. During the examination, her temperature is 38.6°C and she has a rash with small blisters on her trunk. The knee feels warm to touch and is immobile. Attempts to flex or extend the knee are unsuccessful. A joint aspiration is done, and Gram-negative diplococci are observed.
Which of the following antibiotics would be the most suitable to prescribe for this patient?