Sebastian es (3 points) 1) inteligente 2) inteligentes 3) cómicos 4) cómica

The answer is inteligente. Remember you need to have the singular noun matched with the ending of the adjective. Inteligente is singular. Inteligentes is plural and would only be used if two or more people were inteligent. The same goes for comicos. Comica is feminine and Sebastion is masculine so you wouldn't use this choice.