Final answer:
The provided book chapters do not directly compare war to the given options, but the excerpts suggest war is a complex ordeal with elements of an unremitting nightmare and an unending challenge, similar to being lost in a forest or facing a high-stakes game.
Step-by-step explanation:
In the context of the described chapters, Paul does not directly compare war to a singular metaphor such as a game of chess, a journey through a forest, a never-ending nightmare, or a peaceful evening. However, the various excerpts do lend themselves to the interpretation that war, or the experience of conflict, can be a multi-faceted ordeal, embodying elements of an unremitting nightmare due to its fatiguing nature and the feeling of being stuck in an endless forest, symbolizing a possibly insurmountable challenge.
Additionally, the reference to a ballgame in the context of combat suggests that war can sometimes be seen as a game with high stakes. Therefore, none of the given options (a-d) directly corresponds to a specific comparison made in the provided texts, but parts of the texts do resonate with the hardships of war.