Answer:
A. philosophical
Explanation:
It isn't really formal. It has nothing to indicate formality or a conversation in the sentence. It can't really be metaphorical since there's no sign of figurative language either. It seems to be an idea of how the life must be appreciated. A lesson, maybe.
One of the definitions of philosophical is: "having or showing a calm attitude toward disappointments or difficulties."
this seems to fit quite well
