The Apex Organisation for Marketing Cooperatives at the national level is

FCI
NAFED
National Cooperative Union
National Agricultural Marketing Board

The correct answer is (b) NAFED.

NAFED is the National Agricultural Cooperative Marketing Federation of India. It is an apex body of agricultural cooperatives in India. It was established in 1958 by the Government of India to promote and develop the marketing of agricultural produce. NAFED has a network of over 10,000 cooperatives in the country. It undertakes a variety of activities, including procurement, storage, processing, and marketing of agricultural produce. It also provides financial assistance to cooperatives and promotes research and development in the field of agriculture.

The other options are incorrect.

(a) FCI is the Food Corporation of India. It is a state-owned enterprise that is responsible for procurement, storage, and distribution of food grains in India.

(c) National Cooperative Union is a federation of cooperative unions in India. It was established in 1914 to promote and develop the cooperative movement in the country.

(d) National Agricultural Marketing Board is a statutory body that is responsible for regulating the marketing of agricultural produce in India.