Successfully complete the indicated task to unlock the corresponding character:

DeVron: Get 40 Platinum Records for 40 songs. 
Georgia: Get 22 Platinum Records for 22 songs. 
Jessica: Get 35 Platinum Records for 35 songs. 
Kazz: Get 18 Platinum Records for 18 songs. 
Keith: Get 3 Platinum Records for 3 songs. 
Marianne: Get 1 Platinum Record for 1 song. 
Sarah: Get 12 Platinum Records for 12 songs. 
Tyler: Get 1 Diamond Record for 1 song.