The correct answer is B. Group.
A coterie is a small group of people who are close friends or associates. It can also be used to describe a group of people who share a common interest or goal.
A mob is a large, disorderly crowd of people, especially one that is intent on violence or disorder.
A family is a group of one or more parents and their children living together as a unit.
An institution is an organization or establishment established for a social, educational, religious, or commercial purpose.
In this case, the word “coterie” is most closely related to the word “group.” Both words refer to a collection of people who are connected in some way. However, a coterie is typically smaller and more exclusive than a group. Additionally, a coterie often has a shared interest or goal, while a group does not necessarily have this characteristic.