This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to write a reference on couchsurfing
Head to the couchsurfing website.
Just open a web browser on your computer, and go to the couchsurfing website at.
Sign into your couchsurfing account.

Choose from: * If you are new to the site, log in before writing a reference. Enter your email address and password in the fields provided by the site. * You will need to provide the requested personal information, such as your full name, and your login information. After that, just sign in with the account you want to use for the reference. * The log-in button is on the middle of the page. Click it, and enter your username and password on the small log-in window that appears. * To sign up for the account, type in your name, email address, password or social security number into the blanks provided at the top right corner of the page, and click " sign up " at the bottom of the page. Fill out all required fields with no spaces.
The answer is:
The log-in button is on the middle of the page. Click it, and enter your username and password on the small log-in window that appears.