**Core Concept**
The most practical way of treating typhoid carriers involves interrupting the cycle of transmission by eliminating the carrier state. This is crucial in preventing the spread of the disease, particularly in areas with poor sanitation and hygiene.

**Why the Correct Answer is Right**
The correct answer involves administering antibiotics that can effectively eliminate the carrier state by targeting the Salmonella Typhi bacteria in the gallbladder. **Ciprofloxacin** is a fluoroquinolone antibiotic that has been shown to be effective in eradicating the carrier state in 80-90% of cases. The mechanism of action of ciprofloxacin involves inhibiting bacterial DNA gyrase and topoisomerase IV, which are essential for bacterial DNA replication and transcription.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as **Amoxicillin** is not effective in eradicating the carrier state. Amoxicillin is a broad-spectrum penicillin antibiotic that may not penetrate well into the gallbladder, where the bacteria reside.
**Option B:** This option is incorrect as **Metronidazole** is not effective against Salmonella Typhi. Metronidazole is an antibiotic that is effective against anaerobic bacteria and protozoa, but not against gram-negative bacteria like Salmonella Typhi.
**Option C:** This option is incorrect as **Sulfonamides** are not effective in eradicating the carrier state. Sulfonamides are antibiotics that inhibit bacterial folic acid synthesis, but they are not effective against Salmonella Typhi.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the carrier state can persist even after treatment, and therefore, follow-up stool cultures are necessary to confirm eradication.

**Correct Answer:** C. Ciprofloxacin