Concept:The error is in part (c) where the auxiliary verb “has” is incorrect; “is” should be used.
Explanation:The phrase “has unwilling to move” is grammatically wrong.
The structure requires the verb “to be” followed by an adjective: “is unwilling”.
Here, “unwilling” is an adjective describing a state, not a possessive action.
“Has” indicates possession (e.g., “has a car”), which does not fit the meaning.
The sentence means someone is not willing to move, so “is” is the correct linking verb.
Thus, replace “has” with “is” in part (c) to correct the sentence.
The corrected sentence reads: “Persuasion happens only when someone takes a stand from which he is unwilling to move.”
Answer:Option (c)