**Core Concept**
The treatment of latent syphilis involves administering antibiotics to eliminate the causative bacterium, *Treponema pallidum*. The goal is to prevent progression to tertiary syphilis, which can lead to serious complications.

**Why the Correct Answer is Right**
The recommended treatment for latent syphilis is benzathine penicillin G, given intramuscularly (IM) as a single dose. This antibiotic targets the bacterial cell wall, ultimately leading to the death of the microorganism. Benzathine penicillin G is a long-acting form of penicillin, which provides sustained release of the active ingredient and ensures effective treatment of the infection.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because tetracycline and doxycycline are alternative treatments for syphilis, but they are not the first-line choice for latent syphilis. They are typically reserved for patients who are allergic to penicillin or in cases where penicillin is contraindicated.
**Option B:** This option is incorrect because ampicillin is a penicillinase-resistant penicillin, but it is not the preferred choice for treating latent syphilis. Its effectiveness against *T. pallidum* is not well-established.
**Option C:** This option is incorrect because ceftriaxone is a cephalosporin antibiotic, which is not typically used to treat latent syphilis. It may be used for other types of bacterial infections, but it is not the recommended treatment for syphilis.

**Clinical Pearl / High-Yield Fact**
It is essential to note that patients with latent syphilis may be asymptomatic, making regular screening and testing crucial for early detection and treatment. A single dose of benzathine penicillin G is usually sufficient to cure latent syphilis, but follow-up testing is necessary to confirm treatment success.

**Correct Answer: B. Benzathine penicillin G**