Correct option is B
Tobacco chewing increases risk of IUGR, preterm delivery, and intrauterine death. Tobacco-stained amniotic fluid (“tobacco juice fluid”) is a sign of IUD.
Explanation of options: (a) ✘ Polyhydramnios causes excess clear fluid, not tobacco staining. (b) ✔ Correct; tobacco juice appearance of amniotic fluid = IUD marker. (c) ✘ Placenta previa causes bleeding, unrelated to amniotic fluid staining. (d) ✘ GDM affects fetal growth, not amniotic fluid staining.