Mary's Mother Is Diagnosed with Huntington's Disease While Mary Is

Mary's mother is diagnosed with Huntington's disease while Mary is in the first trimester of her first pregnancy. Mary is tested and finds that she carries the Huntington's allele. Mary decides to have amniocentesis because amniocentesis

A) will cure Huntington's disease if it is done early enough in pregnancy.
B) will allow Mary to determine if her child also carries the Huntington's allele.
C) will let Mary know which of her eggs carry the Huntington's allele.
D) is the only way to determine if Mary's husband also has the Huntington's allele.