In the Caro-Kann Advance Variation there are only two good moves that Black can play on move 3: the Bf5 mainline and c5.
This opening line is recommended by many strong International Masters including Levy Rozman a.k.a. Gotham Chess. See https://www.youtube.com/watch?v=ebfzL_GwiIE
3...c5 is known as the Botvinnik-Carls variation or sometimes the Arkell/Khenkin variation
All games in this tournament start with the position after 1.e4 c6 2.d4 d5 3.e5 c5 and you play both the White and Black sides of the board.