A

A girl with primary amenorrhea who has normal breast and pubic-hair development and a normal 46,XX karyotype most commonly has Müllerian agenesis (Mayer-Rokitansky-Küster-Hauser syndrome); ovarian function and secondary sexual characteristics are normal, but the uterus and upper vagina are absent [Bacopoulou, 2014, PMID 24507015]. Turner syndrome lacks breast development and shows 45,X karyotype; androgen-insensitivity has scant pubic hair and 46,XY karyotype; Kallmann syndrome presents with absent secondary sexual traits.