D

Reasoning: Alcohol use, betel-nut (betel-quid) chewing and infection with high-risk human papillomavirus (e.g., HPV-16) are well-documented etiologic factors for head-and-neck squamous cell carcinoma (HNSCC) [Sato, 1987, PMID 3631966; Smith et al., 2010, PMID 20401530]. Epstein-Barr virus, in contrast, is characteristically associated with non-keratinizing nasopharyngeal carcinoma rather than the typical squamous carcinomas of the oral cavity, oropharynx, hypopharynx or larynx, and studies fail to show a consistent link between EBV and HNSCC [López-Llames et al., 2003, PMID 14671923].