68. The specificity of signaling pathways includes all of the following EXCEPT: (A) flippase-catalyzed movement of phospholipids from the inner to the outer leaflet. (B) migration of signal proteins into membrane rafts. (C) phosphorylation of target proteins at Ser, Thr, or Tyr residues. (D) the ability to be switched off instantly by hydrolysis of a single phosphate-ester bond. (E) the assembly of large multiprotein complexes.