Answer:
A.) Background vocalist - A, provides additional vocal support to the main vocalist and other members of a musical group during recordings and performances
B.) Session musician - C, lends support under contract to a musical group's leader and helps in recording or performing live music
C.) Performing artist - D, records music in studios or performs music live in front of an audience
D.) Private instructor - B, independently teaches basic- to professional-level music lessons to a student or group
Explanation: I hope this helped! :]
