It would be "las" because sillas is feminine and it is plural. Las sillas
Es is for other reasons and está is for location
Answer:
2. How old are you?
3. When is your birthday?
4. Where do you live?
5. What's your phone number?
6. What's your email address?
7. What do you like to do?
8. In what grade are you?
9. Do you have any job?
10. Who are your family members?
