What Has Emerged as a Significant Contributor to Delayed Diagnosis

What has emerged as a significant contributor to delayed diagnosis of autism spectrum disorder among children?

A) There are no accurate and reliable diagnostic procedures available to diagnose earlier than 3 years of age.
B) Primary health-care providers often provide passive or reassuring responses to concerns initially expressed by parents.
C) Parents have difficulty identifying typical compared with atypical behaviors in their toddlers.
D) Parents often wait too long, up to 2.7 years, to share developmental concerns with their primary health-care providers.