[Solved] What is the most costly and intrusive form of authentication? A) Something the user knows such as a user ID and password B) Something the user has such as a smart card or token C) Something that is part of the user such as a fingerprint or voice signature D) None of these Cohabitation: Refers to when two people live together in an intimate relationship without being married. Sex Outside: Engaging in sexual activities in outdoor or public settings. Erotic Bond: A deep emotional connection between individuals that includes a sexual aspect, enhancing intimacy. Sexual Relationships: Relationships that involve sexual intimacy or sexual activities between individuals.