The correct option is B mesoderm
In humans, there are three germ layers found in the developing embryo. The outer layer is ectoderm followed by middle mesoderm and inner endoderm. From these germ layers, all the organs and organ systems are developed in the body.
The circulatory system consists of blood, blood vessels, and heart. All these parts of the human circulatory system are derieved from mesoderm.
Ectoderm generally gives rise to different types of epithelial tissues of the nervous system, tooth enamel and the skin.
The endoderm gives rise to some epithelial cells and glands of the gastrointestinal tract, respiratory tract and the renal bladder.