Answer: c. A a secondary group becoming a primary group.
Step-by-step explanation:
The example above signifies a secondary group becoming a primary group. A primary group is a group whereby an individual shows love, support or concern towards others in the group e.g family, church groups etc. The relationships formed here are usually long lasting.
Secondary groups on the other hand are the large groups whereby members typically have impersonal relationships. Since Tristan later became friends with a number of the members and they spent times together, this shows that a secondary group becoming a primary group.