Preventing HIV Spread via Barrier Methods

Steps:

• Identify HIV transmission routes: mainly through blood, semen, vaginal fluids, and breast milk during unprotected sex, sharing needles, or mother-to-child.
• Evaluate prevention strategies: focus on blocking direct fluid exchange.
• Review options: match each to evidence-based methods from health guidelines like CDC.
• Select the most effective: prioritize direct intervention over indirect or ineffective measures.

Why D is correct:

• Condoms act as a physical barrier, preventing exchange of infectious bodily fluids during sex, as defined by HIV transmission epidemiology.

Why the others are wrong:

• A: Exercise boosts immunity but does not block HIV transmission paths.
• B: HIV does not spread through saliva or casual contact like shared cups.
• C: Testing detects infection but does not prevent initial transmission.

Final answer: D