After World War II, the Women's Rights Movement gained momentum as women began to assert their rights and demand equality in various spheres of life, including the workplace, education, and reproductive rights. A significant turning point occurred in the 1960s and 1970s when various social and political actions led to increased visibility and advocacy for women's issues. Among the various organizations that emerged during this period, one played a pivotal role in advocating for gender equality and legal rights, such as the establishment of the Equal Employment Opportunity Commission (EEOC) and the push for the Equal Rights Amendment (ERA). Which of the following organizations is considered instrumental in the modern Women's Rights Movement during this era?