Which of the following refers to the practice of living together and having a sexual relationship without being married?

A) serial monogamy
B) cohabitation
C) common law marriage
D) open marriage

Cohabitation refers to the practice of living together and having a sexual relationship without being married. Serial monogamy refers to the practice of having only one partner at a time but having multiple partners over the course of one's life. Common law marriage refers to a legal status in which a couple who has lived together for a certain period of time is considered married even without a formal ceremony. Open marriage refers to a type of marriage in which the partners have agreed to have sexual relationships with other people outside of the marriage.