or
or
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 by is correct as it indicates an agent. The other options are wrong as from, at, and of indicate the inside of something, a specific location, and a direction respectively. These uses don't fit in the given question. The correct answer is by.
Simple Preposition :
Simple Preposition মূলত একটি word দ্বারা গঠিত হয়।
যেমন: at, on,off, of প্রভৃতি।
