What is the difference between formal and informal groups?
a. an informal group is a committee whose members share a common goal.
b. informal teams get together socially; formal teams do not.
c. an informal group is assigned by an organization or its managers to accomplish a specific purpose.
d. the purpose of a formal group is for friends to get together at a regularly schedule time.
e. a formal group is assigned by an organization or its managers to accomplish specific goals.

e. A formal group is assigned by an organization or its managers to accomplish specific goals.

Explanation:

In an informal group, the formation is voluntarily done by their members in order to socialize so the relationships between them are personal, based on friendship or common tastes, there are no structured hierachy and the flow of information is given between the group members.

In a formal group, all of these characteristics are different:

A formal group is formed by an organization in order to achieve an specific professional goal and there is an hierachy defined by the management for every member of the group . There are also, specific guidelines to follow and the information flow is from one member to the other following  the defined a chain of command. No one can leave or join the group without the management´s authorization. Also, the relationships between members are purely professional.