Correct option is C
The option that contains an error is "to much."
· "To" vs. "Too": "To" is a preposition, often used to indicate direction or purpose. "Too" is an adverb meaning "excessively" or "more than is desirable, permissible, or possible." In the context of the sentence, "too much" is the correct form because it means an excessive amount of seriousness.
· Correct Usage: The phrase "too much" is used to describe an excessive quantity, which fits the context of the sentence.
· Correct sentence: Too much seriousness hardens the world, pinning it down with rules.