“Pertness” refers to boldness, impudence, or being lively in an impertinent way.
The synonym “impudence” means rudeness or disrespectful boldness.
Thus, the correct answer is Option A.
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?