Which dirtbike should I get?

I wanted to know which bike to get, I am 5 7 and about 156 and needed to know if I should get a KX 250, KX 125, or CRF150F, I want to do some trail but not tight woods, just like dirttrack and some open field, I also need somethig that can climb hills and go fast. Please answer ASAP my bday is monday.