a) Wait it out and see what happens. There's always a chance for the other person to come back, but you will need to fix the problems that made you go on a break in the first place, otherwise the relationship will end anyway.
b) Contact them:
i) If person B doesn't respond:
A) Want more time
B) No longer interested and asking for time and space was just an excuse to let them down easy.
ii) If they wanted you back, they would take the initiative to contact you anyway. Why would they need you to do it? You already told them how you feel. Therefore, no point to contact them.
c) No waiting. Quit putting your life on hold and move on.
When someone asks for a break, it means they've given up working on the relationship with the other person. Asking for a break also means that you're ready to loose the other person. Whether the other person comes back to you or not, these two factors will always be in the history books (giving up and prepared to loose the other person).