Robert Bales' Work with the Interaction Analysis Technique Resulted in Principles)

Robert Bales' work with the interaction analysis technique resulted in principles) of successful groups. Which of the following is true?

A) They have someone in the group to focus the group on the task and someone who focuses on maintaining productive relationships
B) They have a leader who has both the skills to solve the problem and good working relationships with the group members
C) Group members have sufficient training to complete the task and they have the autonomy to carry it out
D) They have sufficient supervision to assist them in the task and the task has clear objectives for success
E) Both b and c.