What Happens in Parenting When a Lesbian Mother with a Biological

What happens in parenting when a lesbian mother with a biological child from a previous heterosexual relationship enters into a same-sex relationship?

A) The partners will equally split the household and child-rearing duties.
B) The partners will give up custody to the heterosexual biological parent due to laws.
C) The biological parent will assume most of the parenting responsibility.
D) The partners will take on a more traditional split where the nonworking parent, regardless of biological relation to the child, will take on caregiving duties.