Answer:
The correct answer is Hace un año.
Explanation:
In this case we have a reading comprehension activity. The best thing you can do is read the text as many times as necessary until you fully understand it. You can always help you with a dictionary or a translator.
As for the question, you're being asked <em>"How long ago?" </em>...
What in English we would respond with : <em>"xxx time ago / xxx weeks ago", etc</em>
In Spanish we respond: <em>Hace xxx. (Hace un año, hace una semana, hace un mes, hace un día, etc).</em>