A 20-year-old woman was examined for infertility. She was short (150 cm), had infantile genitalia, ...

A 20-year-old woman was examined for infertility. She was short (150 cm), had infantile genitalia, had no pubic hair, and never had menstruated. She showed webbing of the neck, had cubitus valgus, and widely spaced nipples.
 
  X-chromosome mosaicism was found during the cytogenetic examination. This chromosomal anomaly is a consequence of
  A. nondisjunction during second meiotic division of the ovum
  B. nondisjunction during first meiotic division of the ovum
  C. nondisjunction during spermatogenesis
  D. nondisjunction during mitotic division in early embryogenesis
  E. polyspermia