Answer:
D. Aggregate
Step-by-step explanation:
A social group refers to individuals who interact with one another, share similar characteristics or are working together to achieve a purpose. In this case, A dyad, triad and in-group are types of social groups. Example of social groups include; family, peers, friends
However, In this case Sandy doesn't belong to a social group by definition of what a social group is.
A social aggregate refers to people who are in the same place at a point in time, but who do not necessarily have anything else in common otherwise. Example of a social aggregate are; people at a concert, people in a restaurant, people at a meetup.
From the question, we are told Sandy is in a line for Kanye West tickets, this implies that she part of an Aggregate because, she doesn't have anything else in common with the other people on the line.