Read the passage. True folk songs are composed by average people, not professional musicians. The composers are anonymous—that is, their names are unknown. Singers pass the songs along by word of mouth, often making their own changes until many different versions exist. One reason for the changes is personality—a folk singer puts his or her own stamp on a song, based on his or her own ideas and experiences. A second reason is the oral tradition itself. Because singers learn the songs orally and perform them from memory, they may not reproduce them exactly. A final reason for the changes is familiarity—singers in different regions or time periods make changes that they and their listeners will understand. For example, a song that once told of traveling on a horse may have a later version about traveling on a train and a still later version about traveling in a car. Which phrase in the passage signals a cause? 1.A. one reason B. based on C. for example D. that is 2.A. The singers are professional musicians who like to personalize the songs. B. The singers are average people, not professional musicians. C. The singers compose their songs anonymously. D. The singers want the songs to reflect their culture or region.