Concept:The subject-verb agreement rule requires a singular subject to take a singular verb.Explanation:The subject of the sentence is "The company's phenomenal success".The noun "success" is singular.Therefore, the verb should be singular "is", not plural "are".The error is in part (b) where "are" is used.Parts (a) and (c) have no grammatical mistakes.The correct sentence is: "The company's phenomenal success is largely due to the new director and his team."Answer:Option B