Hemangioblasts are specified by in the
a. vegf, lateral plate mesoderm
b. notch signaling, ectoderm
c. wnt inhibitors, anterior ectoderm
d. fgf2 signaling, splanchnic mesoderm

d. FGF2 signaling, splanchnic mesoderm

Explanation:

Hemangioblasts are the cells that serve as common precursors for blood vessels and blood cells. The hemangioblasts develop from mesenchyme and can give rise to angioblasts (to serve as precursor cells for blood vessels) or pluripotent stem cells to serve as a precursor for blood cells.

The basic fibroblast growth factor (FGF2) is one of the three factors required for initiation of formation of blood vessels. The basic fibroblast growth factor (FGF2) is required for the development of hemangioblasts from the splanchnic mesoderm and their differentiation into angioblasts.

friedrich meischer discovered it in white blood cell