Which Statement Concerning Cyclic Perimenstrual Pain and Discomfort ( CPPD

Which statement concerning cyclic perimenstrual pain and discomfort ( CPPD ) is accurate?

A) Premenstrual dysphoric disorder ( PMDD ) is a milder form of premenstrual syndrome ( PMS ) and more common in younger women.
B) Secondary dysmenorrhea is more intense and medically significant than primary dysmenorrhea.
C) Premenstrual syndrome is a complex, poorly understood condition that may include many symptoms.
D) The causes of PMS have been well established.