Mark the most appropriate preposition from the options given below for blank [15].
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 A)for is correct as it indicates a purpose. The other options are wrong as to, at, and from indicate a direction, a specific location, and a source respectively. These uses don't fit in the given question. The correct answer is A)for.