In the question a 19 year old girl is presenting with primary amenorrhea, she has well developed breast and public hair but on examination uterus and vagina are absent. Since her breast and public hair both are well developed- this means her secondary sexual characteristics are well developed. This means in this female amount of estrogen is adequate, which means she has normally functioning ovaries. Thus, options XYY (presence of Y Chromosome means- gonads are testis), Klienfelter’s syndrome (genotype = 47XXY- again since Y chromosome is present, gonads are testes i.e. they are males) are ruled out and in gonadal dysgenesis gonads are incompletely formed and are streak gonads, M/c example is Turner’s syndrome - genotype 45X0. Since gonads are streak, therefore estrogen is insufficient so secondary sexual characteristics are not well developed. In Turners thus by exclusion, our answer is option b- i.e. Mayer Rokitanskv kuster hauser syndrome.