Phosphatases are a family of enzymes that specifically remove phosphate groups from proteins that were added by protein kinases. Vanadate is an inhibitor of phosphatases in eukaryotic cells. What effect would vanadate have on the response of cells to signals received by receptor kinases?

a. The response of the cell would be shorter than it normally would.
b. The signal would still bind the receptor, so there would be no effect.
c. The response of the cell would last longer than it normally would.