Tristan joined a local land conservation advocacy group because he cares passionately about protecting green spaces. Through his involvement in the group, he became friends with a number of the members. He began spending time with them outside of group meetings and events, getting drinks after work and going on hikes on the weekends. This is an example of which of the following? a. a reference group becoming a secondary group
b. a reference group becoming a primary group
c. a secondary group becoming a primary group
d. a primary group becoming a secondary group