**Core Concept**
Penicillin G benzathine is the primary treatment for syphilis, a sexually transmitted disease caused by Treponema pallidum. This antibiotic targets the bacterial cell wall, inhibiting its growth and proliferation.

**Why the Correct Answer is Right**
Penicillin G benzathine is a long-acting form of penicillin that provides sustained levels of the antibiotic in the bloodstream, ensuring effective treatment of the infection. It is administered intramuscularly, simplifying the treatment regimen and improving patient compliance. The mechanism of action involves the inhibition of transpeptidase enzymes, which are essential for bacterial cell wall synthesis.

**Why Each Wrong Option is Incorrect**
**Option A:** (no information provided)
**Option B:** Other antibiotics such as doxycycline or ceftriaxone may be used as alternatives in cases of penicillin allergy or resistance, but they are not the primary treatment for syphilis.
**Option C:** Macrolides like azithromycin are not the preferred choice for treating syphilis due to concerns about resistance and treatment failure.

**Clinical Pearl / High-Yield Fact**
It is essential to note that syphilis can be asymptomatic in its early stages, making regular screening crucial for early diagnosis and treatment.

**Correct Answer:** B. Doxycycline or Ceftriaxone (in cases of penicillin allergy or resistance).