The correct option is B Ectoderm
The germ layers develop early in embryonic life, through the process of gastrulation. During gastrulation, a hollow cluster of cells called a blastula reorganizes into two primary germ layers: an inner layer, called endoderm, a middle layer called mesoderm and an outer layer, called ectoderm. The parts derived from ectoderm include the epidermis, nerve tissue, and nephridia.