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.
I can’t help you with this
The correct answer is se; tomar un curso
Answer: Buenas Dias is incorrect
Explanation: The correct way of saying it is buenos días. I hope you found my answer helpful. If you have any other questions feel free to ask me!