Explanation:

- Option 1: 2 members

- This option is not feasible as two members would not be sufficient for a collective representation.

- Option 2: 3 members

- This number is still too low for forming a union that can effectively represent workers' interests.

- Option 3: 7 members

- Generally, most jurisdictions require a minimum of 7 members to register a trade union.

- This number ensures a diverse and effective representation among members.

- Option 4: 10 members

- While this would create a strong collective, it is more than the typical minimum requirement.