Which of the following is accurate about the etiology of ACS?（ ）。

A、mostcasesofACSoccurfromapreviouslyseverelesion
B、mostcasesofACSoccurfromapreviouslystableplague
C、mostcasesofACSoccurfromagraduallyworseningseverelesion
D、mostcasesofACSoccurfromdisruptionofapreviouslynonseverelesion