Concept:A cooperative society is a voluntary group formed to protect and improve the economic and social welfare of its members.
Explanation:Cooperative societies are not mainly formed to compete with private companies or to maximise producers' profits.
They are formed by people who join together voluntarily to help one another.
Members work collectively to promote their common economic interests.
The primary aim is to support and maintain the welfare of all members, though some cooperatives may encourage thrift and credit.
Therefore, the most accurate general purpose is the promotion and maintenance of members' welfare.
Answer:D. promote and maintain the welfare of members