The word “books” is a countable noun in plural form, so we use “many” to indicate a large number of countable items.
The sentence should read: “There are many books on the table.”
Thus, the correct answer is (C) many.
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?