**Core Concept**
Human papillomavirus (HPV) is a sexually transmitted virus that causes a variety of lesions, including genital warts, which can manifest as lesions on the penis. HPV is a double-stranded DNA virus belonging to the Papovaviridae family.

**Why the Correct Answer is Right**
HPV infection occurs through skin-to-skin contact, and the virus enters the host cells through microabrasions in the skin. The virus then integrates into the host genome, leading to the production of abnormal proteins that cause the characteristic lesions. HPV types 6 and 11 are most commonly associated with genital warts, while types 16 and 18 are linked to cervical cancer. The lesions caused by HPV on the penis can be flat, raised, or cauliflower-like in appearance.

**Why Each Wrong Option is Incorrect**
**Option A:** Treponema pallidum is the causative agent of syphilis, which presents with a painless chancre on the penis, not a lesion caused by HPV.
**Option C:** Epstein-Barr virus (EBV) is associated with infectious mononucleosis, Burkitt lymphoma, and nasopharyngeal carcinoma, but not with lesions on the penis.
**Option D:** Human herpesvirus 6 (HHV-6) causes roseola in children and has been linked to encephalitis, but it is not associated with genital lesions.

**Clinical Pearl / High-Yield Fact**
HPV is a leading cause of sexually transmitted infections worldwide, and vaccination against HPV types 6, 11, 16, and 18 has been shown to reduce the incidence of genital warts and cervical cancer.

✓ Correct Answer: B. HPV