In this sentence, “great teachers” is a general statement. When talking about general things or plural nouns that do not refer to a specific group, we do not use any article.
The correct sentence is: “This school has great teachers.”
Thus, the correct answer is (D) No article required.
Arun’s present age in years is 40% of Barun’s. In another few years, Arun’s age will be half of Barun’s. By what percentage will Barun’s age increase during this period?