The Text Describes Two Alternate Explanations for the Increased Rate

The text describes two alternate explanations for the increased rate of autistic disorder, which are

A) unhealthy changes in the American diet and increased rates of genetic abnormalities.
B) increased exposure to lead and increased environmental pollution.
C) changes in diagnostic practices and the addition of two new disorders to the autism spectrum category.
D) reactions from other childhood vaccinations and the inclusion of a comorbid autism disorder for children with intellectual disability.