Final answer:
Subunit vaccines are the most effective prevention against cancers caused by certain genotypes like HPV. Antiviral medications such as acyclovir can manage herpes symptoms but do not prevent HPV-related cancers.
Step-by-step explanation:
The most effective way to prevent infections with genotypes that cause genital, rectal or oral cancer is through vaccination. Among the options provided, subunit vaccines (C) are a type of vaccine designed to generate an immune response by using specific pieces of the pathogen, such as its proteins, rather than the whole organism. Subunit vaccines, like the HPV vaccine, are designed to prevent diseases such as genital warts and cancers caused by human papillomavirus (HPV). While antiviral medications like acyclovir can treat genital herpes by reducing the number and severity of outbreaks and have been essential in managing the symptoms, they do not prevent cancers associated with genotypes like HPV. Likewise, antiviral drugs like Tamiflu are used primarily for treating specific viral infections such as influenza and do not prevent HPV-related cancers.