Choose the option that fills the blank with the most suitable word:
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)after is correct as it means following in order,time etc. The other options are wrong as in, from, and as indicate the inside of an area, a source, and a reason respectively. These uses don't fit in the given question. The correct answer is C)after.