• Context and Grammar: The sentence uses the structure "too + adjective + to + verb." This is a common English construction used to indicate that something is "to an excessive degree," making a certain action impossible or difficult.
Meaning: In this context, "too" means "more than what is desirable or possible." The sentence implies: He is so tired that he cannot finish his homework.
Spelling: "Too" is an adverb of degree, whereas "To" (Option A) is a preposition or part of an infinitive.