Ms. Gardner is currently enrolled in an MA-PD plan. However, she wants to disenroll from the MA-PD plan and instead enroll in a Part D only plan and go back to Original Medicare. According to Medicare's enrollment guidelines, when could she do this?

A. She may only make such a change during her "initial coverage election period," which occurred when she first became entitled to Medicare.
B. She may do it only during the MA Disenrollment Period, which runs from January 1 to February 14 of each year.
C. She may make such a change during the Annual Election Period that runs from Oct. 15 to December 7, or during the MA Open Enrollment Period which takes place from January 1 - March 31 of each year.
D. Any time that she is dissatisfied with the plan's network coverage or customer service, she may make such a change.