Insulinlike growth factors IGFs somatomedins are necessary f
     Insulinlike growth factors (IGFs, somatomedins) are necessary for the full effect of:  insulin  hGH  GnRH.  T_3 and T_4.  glucagon. 
  
  Solution
Answer :B
Reason: fundamental action of IGFs is to stimulate growth like:Epidermal growth,Platelet growth,Nerve growth.
It works in highly cascadial manner:
Hypothalmus works on Pitutary by releasing neurohormone, Pitutary releases RH like IGFs which influences growth of epidermis,platelet and nerve.

