<prompt> Severe mental retardation is -50-7035-5020-3520  <response>: Ans is c i.e. 20 - 35 o Normal IQ - 90-109;o Borderline IQ - 70-89;o Mild mental retardation IQ - 50-69;o Moderate mental retardation IQ -35-49;o Severe MR IQ - 20-34;o Profound MR IQ - 0-19. 