8027. It is quite unseemly that person should so behave with his elders.

✅ The correct answer is option D.
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