It is quite unseemly that person should so behave with his elders.

A. childish

B. ugly

C. discourteous

D. improper

Answer: Option D

Solution(By Examveda Team)

Childish : of, like, or appropriate to a child.
Ugly : unpleasant or repulsive, especially in appearance.
Discourteous : showing rudeness and a lack of consideration for other people.
Improper : not in accordance with accepted standards, especially of morality or honesty.
Unseemly : (of behaviour or actions) not proper or appropriate.

Synonym of Unseemly is Improper