Fill in the blanks with suitable prepositions:
A preposition is a word which comes before a noun or a pronoun and establishes a relationship between the elements of a clause or words. Option C)to/to is correct as to is used to express a connection and an extreme state. The other options are wrong as on, with, by, and at indicate a surface, inclusion, usage, and a specific location respectively. These uses don't fit in the given question. The correct answer is C) to/ to.