What type of legal document outlines the rights and duties of parties within a marriage?

A prenuptial agreement is the correct choice because it is specifically designed to outline the rights and duties of parties within a marriage before it takes place. This type of legal document typically addresses important issues such as property ownership, financial responsibilities, and other personal rights, providing clarity and protection for both parties in the event of a divorce or separation.

In contrast, a custody agreement focuses on the arrangements regarding the care and guardianship of children and does not address the personal rights and duties of spouses. A separation agreement is made when a couple decides to live apart but typically reflects the terms of their separation rather than the rights and duties within the marriage itself. A divorce decree, on the other hand, is issued at the conclusion of a marriage, documenting the terms of the divorce and the agreements made post-marriage rather than preemptively defining the rights and responsibilities during the marriage. Thus, the prenuptial agreement serves a unique and critical role in establishing the expectations and obligations of both parties entering into a marriage.