Which of the following embryonic membranes forms part of the umbilical cord and contributes to the formation o

Which of the following embryonic membranes forms part of the umbilical cord and contributes to the formation of the urinary bladder?

A amnion
B allantois
C fertilization envelope
D chorion

B. allantois

The allantois is part of and forms an axis for the development of the umbilical cord, in placental mammals (like humans).

The function of the allantois is to collect liquid waste from the embryo, as well as to exchange gases used by the embryo.