English is taught . . . . . . Kishan sir to us very easily. A. of B. by C. for D. with

The correct answer is: by.

The preposition “by” is used to indicate the agent or cause of an action. In this case, the action is “teaching” and the agent is “Kishan sir”. Therefore, the correct answer is “English is taught by Kishan sir to us very easily.”

The other options are incorrect because they do not make sense in the context of the sentence. The preposition “of” is used to indicate possession or association. The preposition “for” is used to indicate the purpose or benefit of an action. The preposition “with” is used to indicate the instrument or means by which an action is performed.

Here are some examples of how the other prepositions could be used in a sentence:

• English is a subject that is taught in schools.
• The book is for you.
• I cut the bread with a knife.