Of the four given options, choose the most appropriate one.

Correct option is B

The correct answer is (b) His knowledge of Indian vernaculars is far superior to that of the common man.
The subject "knowledge" is singular, so the verb must agree with it. "Is" is the correct singular verb. The phrase "far superior to that of" is also correctly used to compare the subject's knowledge with that of the common man.
Grammatical Rule in English:
The rule of subject-verb agreement states that a singular subject takes a singular verb, and a plural subject takes a plural verb.
Grammatical Rule in Hindi:
Subject-Verb Agreement का नियम कहता है कि अगर कर्ता (subject) एकवचन (singular) है, तो क्रिया (verb) भी एकवचन होनी चाहिए। और अगर कर्ता बहुवचन (plural) है, तो क्रिया भी बहुवचन होगी।
· उदाहरण:
· सही: His knowledge is remarkable.
· गलत: His knowledge are remarkable.
· यहां "knowledge" एकवचन है, इसलिए "is" का प्रयोग किया गया है।