B10 · 1. e4 c6
The best blend of solidity and simplicity against 1.e4. The plan behind 1...c6 and 2...d5 is transparent, your light-squared bishop gets out before the pawn chain closes (the French player's eternal complaint), and the resulting structures stay sound from beginner to grandmaster level.
Best for: Players who want one dependable answer to 1.e4 for their whole chess life.
Learn the Caro-Kann Defense (vs 1.e4) move by move