Anuclear family is which of the following?
one parent and his or her children
. a biological family along with "fictive kin."
two parents and their children.
a husband with two or more wives.

A nuclear family is two parents and their children. This has long been considered the "traditional" or "central" (thus nucleus or nuclear) type of family even though the dynamics of what constitutes a family has changed significantly in recent years. In a nuclear family, the parents are married and can have any number of children (that they conceived together).

It would be two parents and their children because their altogether!