The correct answer is: B. ectoderm, mesoderm, endoderm.
The three germ layers are the ectoderm, mesoderm, and endoderm. These layers are formed during the early stages of embryonic development and give rise to all of the tissues and organs of the body.
The ectoderm is the outermost layer of cells in the embryo. It gives rise to the skin, hair, nails, teeth, nervous system, and sense organs.
The mesoderm is the middle layer of cells in the embryo. It gives rise to the bones, muscles, blood, connective tissue, and reproductive organs.
The endoderm is the innermost layer of cells in the embryo. It gives rise to the lining of the digestive tract, respiratory tract, and urinary tract.
The three germ layers are essential for the development of a healthy embryo. If any of the layers is not formed correctly, it can lead to birth defects.