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 B)by/on is correct as they indicate a medium and a method/manner respectively. The other options are wrong as with indicates inclusion and on cannot be used in the second blank as it doesn't act as an agent. These uses don't fit in the given question. The correct answer is B)by/on.