Nosotros somos de Guatemala.
Because ser is for more permanent things, like character traits or nationalities, while estar is more for temporary things like feelings or current location
How to remeber ser and estar easy
for how you feel or where you are, always use the verb estar
D.Interior Coumtry
Hope This Help You
Answer:
dormirse
Dormirse means falling asleep
I believe it is son because the pens will not just go from being old pens to being new pens.