identify the labelled parts A-D in the given figure of human foetus within the uterus.
A. `{:(,A,B,C,D),(,"Placental villi","Umbilical cord","Yolk sac","Embryo"):}`
B. `{:(,A,B,C,D),(,"Umbilical cord","Placental villi","Allantois","Embryo"):}`
C. `{:(,A,B,C,D),(,"Umbilical cord","Placental villi","Yolk sac","Embryo"):}`
D. `{:(,A,B,C,D),(,"Umbilical cord","Placental villi","Embryo","Yolk sac"):}`