A karyotype reveals that a woman is carrying a fetus that has 47 chromosomes. The test reveals that the genotype of the fetus is XXY. Which of the following statements is correct?

A) This is a trisomy.
B) This is Turner syndrome.
C) The fetus has Klinefelter syndrome, and most likely a nondisjunction event occurred in the mother during egg formation.
D) This is an autosomal trisomy.