Answer: Friends are mostly peer or per group
Explanation:
Peer group or peer is the group of people that contain the individual who have almost same age as the person along with similar interest,background, work social status. These members of peer group can influence and impact behavior of each other .
According to the question,Elizabeth does not understand the concept of friend are mostly peer as they have similar age and interest. Thus, boss and professor did not accept invitation for coffee of Elizabeth as they are not her peer. They do not belong to same age group and social background.