Vascular endothelial growth factor (abbreviated as vegf and pronounced "veg-f") is apeptide- signaling molecule related to platelet-derived growth factor. vegf is important in theformation of the circulatory system because its signaling pathway causes the formation ofnew blood vessels in developing embryos during normal development. it also causes theformation of new blood vessels that supply tumors when the tumor produces and secretesvegf. given what you know about the different kinds of cell signaling and about vegf, which of the following is true?

a. vegf is an endocrine-signaling moleculebecause it circulates in the bloodstreaminside of platelets.
b. vegf is an endocrine-signaling moleculebecause it is released from platelets into thebloodstream where it is carried throughoutthe body, causing widespread activation ofpdgf receptors on cells in a variety oftissues.
c. vegf is a paracrine signaling moleculebecause it binds to vegf receptors on cellsat the site where new blood vessels areneeded.