Respuesta :

Simpatico= friendly/nice
Serio= serious
Triste= sad

Your task was to choose the word that best fits with the given word above. Viewing the definitions, I'd say the correct answer is Simpatico. The reason why I chose this is because usually a happy person is friendly/nice, so that's more of a common sense answer.
The correct answer would be Feliz. The word happy in Spanish is "Feliz" simpatico is a person who is nice serio is a person who is serious and triste is a person who is sad. Simpático would be a good answer but seeing as that u are asked to choose the Spanish equivalent of the word it would be "Feliz"