A form of marriage in which each married partner is allowed only one spouse at any given time

Common-law marriage, also known as sui iuris marriage, informal marriage, marriage by habit and repute, or marriage in fact, is a legal framework in a limited number of jurisdictions where a couple is legally considered married, without that couple having formally registered their relation as a civil or religious marriage.

The original concept of a "common-law marriage" is a marriage that is considered valid by both partners, but has not been formally recorded with a state or religious registry, or celebrated in a formal religious service. In effect, the act of the couple representing themselves to others as being married, and organizing their relation as if they were married, acts as the evidence that they are married.

The term common-law marriage has wide informal use, often to denote relations that are not legally recognized as common-law marriages. The term common-law marriage is often used colloquially or by the media to refer to cohabiting couples, regardless of any legal rights that these couples may or may not have, which can create public confusion both in regard to the term and in regard to the legal rights of unmarried partners.

the correct answer is d