Concept:A cooperative society is a voluntary association formed to promote the common economic welfare of its members.
Explanation:Members pool their resources together to achieve shared goals in production, distribution, and consumption.
The central aim is to protect members' interests and pursue their welfare, not to earn profit for outsiders.
Other options such as maintaining integrity, ensuring working conditions, or offering voluntary services are only secondary features.
Therefore, the basic principle is best captured by safeguarding and promoting the welfare of members.
Answer:B. protect the interest and pursue welfare of members.