8) Marco and Roberto have a chocolate bar made up of 8 squares, one of which (the one at the top left) is not good. They decide to play this game. On each turn, each player breaks the chocolate bar into two along one of the lines separating the squares, and then eats the part that does not contain the bad square. The player who leaves the opponent with only the bad square wins. Knowing that Roberto is the first to play, what should he eat to be sure of winning?

(A) the two squares on the far right (B) the four squares on the far right

(C) the six squares on the far right (D) the four squares at the bottom

(E) no matter what move he makes, Roberto loses!
8) The answer is (B)

Indeed, by doing so, Roberto finds himself in this situation:

![](https://cdn.mathpix.com/cropped/2024_04_17_df6134ed1e07189e6736g-2.jpg?height=126&width=146&top_left_y=200&top_left_x=1452)

At this point, it is clear that, whatever move Marco makes, Roberto wins on the next move. Moreover, with similar reasoning, it is verified that moves (A), (C), and (D) are losing for Roberto.