best counter to caro kann?


There is no such thing as 'best' in normal openings. It depends on your playing style and what your normal opponent prefers to play.
2 knights defence are fine. After 1.e4 c6 2.Nc3 (or 2.Nf3 d5 3.Nc3) 2...d5 3.Nf3 you will have to study the two main moves: 3...dxe4 and 3...Bg4. Then you are ready to play.
Later on you may take some time to also study 3...Nf6, 3...d4, 3...e6, 3...g6 etc. according to what your opponent plays.