What is the most effective way to prevent contraction of the HIV virus?

Correct option is B

Consistent condom use is the most effective prevention method against HIV, particularly during sexual contact. Explanation of options:
· (a) ✘ Not effective for direct person-to-person sexual transmission.
· (b) ✔ Correct; condoms prevent fluid exchange.
· (c) ✘ Important, but not universally applicable.
· (d) ✘ More relevant in clinical settings.