<human>: Hey /r/relationships 21 years old; male
Okay here is the deal I'm labeling the girls in this explanation to keep the story straight not to be disrespectful. 

Girl A (age19): Just broke up with her.  We dated had been dating a little over a year. I broke it off; wasn't happy with the relationship

Girl B (age 22): Is another ex to which we also dated for a year. Dated before A. 

Girl C (age 22): Is a girl I just started talking to after braking up with Girls A. Been talking for a week. 

OK here is the story. After braking up with Girl A I started talking to Girl C. I really like Girl C and like the way things are going, however during the week we have been talking, Girl B has contacted me. 

Girl B and I wanting to catch up on old times decided to hangout one night. One thing led to another and we hooked up. She had recently broke up with her boyfriend as well. I regret hooking up and I know she doesn't want anything emotionally involved with our hook up. 

Now the Question is: Should I tell Girl C about the hook up? Seeing that we like each other and that I don't wish to start a relationship off on the wrong foot, I feel like I should. The thing is we only have been talking for a week, and I do not want to turn nothing into something. If I decide to tell her, how would go about doing this? I really want to continue talking to Girl C, if it is possible.

Can you condense the text into three sentences or less?
<bot>: Broke up with A, started talking to C, while talking to C slept with B. Should I tell C about my hookup with B? And how should I do this?