Hola!! Your answer for this question is oficina de correos.
1.) If you translate the question you get:
I need to buy an envelope in a ____
post Office
Bank
Bakery
Museum
2.) From the options, the best answer will be the Post Office. You can buy an envelope there.
1. Los lápices
2. Los calendarios
3. Las profesoras
4. Las escuelas
5. Los borradores
6.los relojes
Your welcome
