Answer: B. Endoderm Formation
Step-by-step explanation:
Embryonic development is a 9 month long period. right after implantation, endoderm formation takes place.
The endoderm is one of the layers of germs that were developed during embryonic development and leads to development of the cells that line the organs.
During endoderm formation, tissue fusion takes place in which two opposing tissues come in contact and get fused to form one continuous structure. It can affect the formation of many organs, including the palate, optic cup, heart and neural tube
Hence, the correct option is B.