Which of the Following Statements Most Appropriately Differentiates an Informal

Which of the following statements most appropriately differentiates an informal group from a formal group?

A) Only an informal group is formed from the day-to-day interactions of individuals.
B) Only an informal group is a small number of individuals who communicate person-to-person.
C) Only an informal group is specifically created by management.
D) Only an informal group is a small number of individuals who work to achieve one or more common goals.