Which of the following is a non-governmental organization known for providing medical aid?

The organization known for providing medical aid among the options is Doctors Without Borders. This non-governmental organization, also known as Médecins Sans Frontières (MSF), has a specific focus on delivering emergency medical assistance to populations affected by conflicts, epidemics, natural disasters, or exclusion from healthcare. They are widely recognized for their independent medical humanitarian work across the globe, often in regions where other organizations may not have access or capacity.

While Oxfam, Christian Aid, and CAFOD also engage in humanitarian work, their primary focus lies in addressing poverty, conflict, and development issues rather than specifically concentrating on medical aid. Thus, Doctors Without Borders stands out as the organization explicitly dedicated to providing healthcare services in crisis situations.