Family and Twin Studies Examining the Rates of Autism Spectrum

Family and twin studies examining the rates of autism spectrum disorder have provided compelling evidence for a genetic influence in the development of the condition.In fact,the concordance rate of autism spectrum disorder was ______ in identical twins (Ronald & Hoekstra,2011) .

A) 24% to 28%,or maybe slightly less
B) varying between 40% and 49%
C) steady,at 50% to 55%
D) 76% to 88%,and possibly more