**Core Concept**
Epstein-Barr Virus (EBV) is a member of the herpesvirus family and is known to be associated with various malignancies, particularly those of epithelial and lymphoid origin. EBV has been implicated in the pathogenesis of several cancers, but its role is most strongly established in nasopharyngeal carcinoma.

**Why the Correct Answer is Right**
EBV causes nasopharyngeal carcinoma through a complex interplay of viral and host factors. The virus infects epithelial cells in the nasopharynx, leading to the activation of oncogenes and the suppression of tumor suppressor genes. This results in uncontrolled cell growth and tumor formation. The association between EBV and nasopharyngeal carcinoma is well-documented, with EBV DNA detected in tumor cells from affected individuals.

**Why Each Wrong Option is Incorrect**
**Option A:** Cervical cancer is primarily caused by Human Papillomavirus (HPV), not EBV. HPV infection leads to the development of cervical intraepithelial neoplasia, which can progress to invasive cervical cancer.
**Option C:** Lung cancer is caused by a variety of factors, including smoking, exposure to carcinogens, and genetic predisposition. EBV is not a known risk factor for lung cancer.
**Option D:** Endometrial cancer is a malignancy of the uterine lining, and its causes are multifactorial, including hormonal influences, genetic mutations, and environmental factors. EBV is not associated with endometrial cancer.

**Clinical Pearl / High-Yield Fact**
EBV is also known to cause infectious mononucleosis, a condition characterized by fever, sore throat, and lymphadenopathy. This condition is often referred to as "mono" or the "kissing disease."

**✓ Correct Answer: B. Ca Nasopharynx**