Which of the following is true according to the leader$$member exchange theory?

a$.$ Leaders are more likely to empower group members with whom they have a high$-$quality exchange.

b$.$ Managers are more likely to act as servant leaders toward subordinates with whom they have low$-$quality exchanges.

c$.$ Leaders develop entirely different relationships with each group member and treat no two alike.

d$.$ If most group members feel that they have good exchanges with the leader, being treated a little differently by the leader affects their performance.