What counts as 'close combat' in Hitman: Blood Money?
Solution 1:
3. and 4. are the only ones besides fiberwire!
The difference though is that you cannot kill with sedative, so as you stated on your own injecting with poison is your 3rd CQ-Kill. You almost always use sedative on non-target-people and should use poison and fiberwire to kill for geting max stealth rating.
(Source and some tipps as well)