G Protein Coupled Receptors Are a Large Class of Receptors

G protein coupled receptors are a large class of receptors that bind hormones as well as other signaling molecules,neurotransmitters,and even odorants.They are a major target of pharmaceutical drugs for various disorders.Typically,the drug acts as an antagonist,blocking the binding site on the GPCR.Why is the receptor a more attractive drug target than the G protein activated downstream? (Check all that apply.)

A) It is easier to target molecules from the outside of the cell membrane,because getting drugs into the cell can be difficult.
B) Interfering with the G protein would require getting a drug across several membranes into the cell's nucleus.
C) The "G-protein" is not really a protein but just a GTP molecules,which is too small to be a possible drug target.
D) Since GPCRs are so widespread and perform many roles in the body,targeting G proteins used by multiple GPCRs would create side-effects beyond the targeted physiological function.
E) Since the GPCRs bind a variety of unique ligands,their structures are varied enough to be able to create specific targeted drugs for certain pathways.