Which pair of taxpayers is entitled to split various benefits for one dependent child?

A. A father and mother who have never married and have not lived together for the last six months of the year, whose child is the custodial parent's qualifying child.

B. A father and mother who have never married and have not lived together for the last six months of the year, whose child is their qualifying relative.

C. A grandmother and mother who share a qualifying child.

D. A grandmother and grandfather who are divorced, whose grandchild is the custodial grandparent's qualifying child.