The correct answer is D. Hace un mes que
This is a Spanish expression that you need to memorize. This expression is always like this: hace un mes que. In English, this literally is translated as: It's been a month that. So in this way we can write some sentences as follows:
1. Hace un mes que no te veo
I have not seen you for one month
2. Hace un mes que llegaste a mi vida
You came into my life a month ago.
3. ¡Hace un mes que te fuiste, papá!
you passed away a month ago, father!
4. Hace un mes que no bailo.
I have not danced for one month.