Secondary amenorrhea is defined as

A: absence of menstruation for 12 months
B: absence of menstruation for 6 normal menstrual cycles
C: absence of menstruation for 3 normal menstrual cycles or 6 months
D: absence of menstruation for 6 normal menstrual cycles or 9 months
E: absence of menstruation for 9 normal menstrual cycles or 2 months

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