The correct answer is option 'B', the National Disaster Management Authority (NDMA).

The Prime Ministers National Relief Fund (PMNRF) is a fund set up by the Government of India to provide immediate relief to people affected by natural disasters, such as earthquakes, floods, cyclones, and other calamities. It was established in 1948 and is solely dependent on public contributions.

The PMNRF is operated by the National Disaster Management Authority (NDMA), which is an apex body responsible for disaster management in India. The NDMA was established in 2005 under the Disaster Management Act, with the Prime Minister as its chairperson. It is responsible for laying down policies, plans, and guidelines for disaster management and coordinating the efforts of various government agencies and other stakeholders.

The role of the NDMA in operating the PMNRF can be understood by looking at its functions and responsibilities:

1. Policy Formulation: The NDMA formulates policies, plans, and guidelines for disaster management. It sets the framework and guidelines for the operation of the PMNRF.

2. Coordination: The NDMA coordinates the efforts of various government agencies, departments, and organizations involved in disaster management. It ensures that the funds from the PMNRF are effectively utilized for providing relief to the affected people.

3. Resource Mobilization: The NDMA mobilizes resources, both financial and material, for disaster management. It works towards generating public awareness and support for the PMNRF, encouraging donations from individuals, organizations, and corporates.

4. Monitoring and Evaluation: The NDMA monitors and evaluates the utilization of funds from the PMNRF to ensure transparency and accountability. It reviews the effectiveness of relief measures and takes corrective actions if needed.

5. Capacity Building: The NDMA conducts training programs, workshops, and seminars to build the capacity of various stakeholders in disaster management. It aims to enhance the preparedness and response capabilities of individuals, communities, and organizations.

In conclusion, the Prime Ministers National Relief Fund is operated by the National Disaster Management Authority (NDMA), which is responsible for policy formulation, coordination, resource mobilization, monitoring and evaluation, and capacity building in disaster management.