Seo-yeon owns a condominium. In each of the following alternative situations, determine whether the condominium should be treated as a residence or a non residence for tax purposes.
a) Seo-yeon lives in the condo for 19 days and rents it out for 22 days.
b) Seo-yeon lives in the condo for 8 days and rents it out for 9 days.
c) Seo-yeon lives in the condo for 80 days and rents it out for 120 days.
d) Seo-yeon lives in the condo for 30 days and rents it out for 320 days.