Answer:
¿Cómo es (ella)?
Step-by-step explanation:
The translation of this is: How is she, the student responed with " she is quite active, and a little serious"
The other options in order would mean:
Where is she?
What is her name?
How is she? (using conjugation of ser)
How is she? (usint conjugation of estar)
The correct word to use for this situation is ser therefor C is correct
i know this is late but it still hope it helps! <3