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

The correct answer is C. discourteous.

The word “unseemly” means “not appropriate or fitting.” In this context, it is being used to describe the person’s behavior towards his elders. The other options are not as relevant to the context of the question.

• Childish: This option is not as relevant to the context of the question because it does not specifically address the person’s behavior towards his elders.
• Ugly: This option is not as relevant to the context of the question because it does not specifically address the person’s behavior towards his elders.
• Improper: This option is not as relevant to the context of the question because it does not specifically address the person’s behavior towards his elders.

The word “discourteous” is the most relevant option because it specifically addresses the person’s behavior towards his elders. The person’s behavior is not appropriate or fitting because he is not showing respect to his elders.