Concept:A trade association protects and promotes the common interests of businesses within the same trade or industry.
Explanation:Trade associations do not pay salaries, provide loans, or create jobs as their main duties.
Such functions belong to employers, banks, or government agencies.
The main aim of a trade association is to safeguard members' interests and improve their general welfare.
This includes advising members, setting trade standards, and representing them in policy matters.
Therefore, the correct choice is promoting members' welfare.
Answer:B. promote members' welfare