This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
A 19 year old patient presents with primary amenorrhoea. She has well developed breasts and axillary and pubic hair. Uterus and vagina are absent. The diagnosis is most likely: 
Select and explain. 
A. XYY syndrome, B. Gonadal dysgenesis, C. Mullerian agenesis, D. Klinefelter's syndrome
C: Mullerian agenesis
Answer: C: Mullerian agenesis 
Explanation: Mullerian agenesis (Mayer-Rokitansky-Kuster-Hauser syndrome) is the second most common cause of primary amenorrhea. Clinical features: Normal ovarian development Normal endocrine function Normal female sexual development Shoened or absent vagina in addition to absence of the uterus Individuals have 46,XX karyotype Ref: Rosen M.P., Cedars M.I. (2011). Chapter 13. Female Reproductive Endocrinology and Infeility. In D.G. Gardner, D. Shoback (Eds),Greenspan's Basic & Clinical Endocrinology, 9e.