A 29 yrs old woman with a pregnancy of 17 week has a 10 years old boy with down syndrome. She does not want another down syndrome kid; best advice to her is
A
No test is required now as her age is below 35 years
B
Ultra sound at this point of time will definitely tell her that next baby will be down syndromic or not
C
Amniotic fluid samples plus chromosomal analysis will definitely tell her that next baby will be down syndromic or not
D
blood screening at this point of time will clear the exact picture