**Core Concept**
The question requires knowledge of the appropriate antibiotic treatment for Shigella infections, which is a common cause of bacterial dysentery characterized by bloody diarrhea and fever. Shigella species are gram-negative bacteria that invade the intestinal mucosa, leading to inflammation and fluid loss.

**Why the Correct Answer is Right**
The drug of choice for Shigella infections is ciprofloxacin, a fluoroquinolone antibiotic. Ciprofloxacin works by inhibiting bacterial DNA gyrase and topoisomerase IV, enzymes essential for bacterial DNA replication and transcription. This leads to the death of the bacterial cells. The use of ciprofloxacin is particularly effective against Shigella species, which are often resistant to other antibiotics such as ampicillin and trimethoprim-sulfamethoxazole.

**Why Each Wrong Option is Incorrect**
**Option A:** Amoxicillin is not effective against Shigella species as they are often resistant to this antibiotic.
**Option B:** Metronidazole is used to treat amoebiasis, not bacterial dysentery caused by Shigella.
**Option C:** Ceftriaxone is a cephalosporin antibiotic that may not be effective against Shigella species, and its use is also limited by its high cost and potential for resistance.

**Clinical Pearl / High-Yield Fact**
It is essential to note that the use of antibiotics for Shigella infections should be based on laboratory confirmation of the diagnosis, as empirical treatment may lead to unnecessary exposure to antibiotics and potential resistance.

**Correct Answer: C. Ciprofloxacin**