Explanation:

• Disjunctive Group: This is the correct option. A disjunctive group restricts membership such that members can only belong to one group of its kind at a time.

• Overlapping Group: This type of group allows individuals to be part of multiple groups simultaneously. There are no restrictions on being a member of similar groups.

• Genetic Group: This term typically refers to groups formed based on genetic similarities or connections, not about restrictions on joining similar groups.

• Secondary Group: These are large, impersonal groups with short-term relationships. They don't necessarily restrict membership in similar groups.