Primary amenorrhea may be attributed to:

Rationale: A. Polycystic ovarian syndrome (PCOS) typically causes secondary amenorrhea, not primary amenorrhea, as menstruation usually begins normally. B. Hyperprolactinemia can lead to secondary amenorrhea by disrupting the hypothalamic-pituitary-ovarian axis. C. Turner's syndrome, a chromosomal disorder (45,X), is a common cause of primary amenorrhea due to gonadal dysgenesis, resulting in absent or delayed puberty. D. Ovarian failure usually leads to secondary amenorrhea after menarche, rather than primary amenorrhea.