You Are Babysitting Your Friend's Autistic Child

You are babysitting your friend's autistic child. You have known them all of their life and think of them as part of your own family. While their sometimes unusual behaviour was confusing to you when you were initially getting to know them, as you learned more about Autism you gained a much better understanding of why they behave the way they do. They seem to be extremely confused lately and you can't help but feel reminded of how one of your grandparents used to behave just before they were diagnosed with dementia. You wonder if, even just theoretically, someone as young as this child could be diagnosed with dementia. Is that possible?

A) no, dementia diagnoses cannot apply to anyone under 18
B) no, dementia diagnoses cannot apply to anyone under 50
C) yes, people of any age can be diagnosed with dementia
D) yes, but only if the child is a carrier for a rare genetic variant that has been identified
E) yes, but only in a culture that has rejected the use of the DSM