Which Statement Concerning the Etiology of Autism Is Correct

Which statement concerning the etiology of autism is correct?

A) The most common etiological basis of autism noted so far is parental neglect or detachment.
B) The early lack of normal development suggests biological rather than psychosocial factors.
C) Researchers believe that there is one cause for autism that has yet to be discovered.
D) Although psychological effects are important, biological factors play the most critical role.