The best response is:

c. Wait until you get back home to check your email. After all, you'll be back in a week.
It's not an emergency and you only have a week to wait, so it's better to hold off on checking your email than to put yourself in danger by going into stranger's house or disclosing private information like your password. You might chose D if you didn't have to travel so far and pay a lot of money to use the Internet.