Viper venom must enter the bloodstream to cause harm - it is a protein-based toxin that affects blood circulation and tissue. When it remains outside the circulatory system (on skin, in a wound, or swallowed), it is typically broken down by digestive enzymes or cannot reach vital organs. Swallowing venom (B) is generally safe unless you have open wounds, killing the snake (C) doesn't neutralize existing venom, and immediate treatment (D) is only relevant if already injected.