I'd need more information on the choices. In my own case, biology wouldn't decide the matter.
Broadly considered, whomever would be more capable of providing the better environment and support.
What would you choose: being raised by your single biological mother or by an adoptive couple?
It all depends upon the circumstances. If my biological mother isn't capable of properly caring for a child, I would rather be raised by adoptive parents (and perhaps connect with her later in life if she's open to that).