After four-year-old Sachtay moved from one preschool to another, he began sucking his thumb, something he had not done since he was two. What is this called?
Group of answer choices

a learning disability
regression
a mental disability
autism

The answer is regression.

Explanation:

Sometimes when there is a big change in a young child or toddler's environment or daily routine, they will regress in the only way they know.    This can occur in different situations such as toilet training or any kind of big move or change in their lives.  It's not a learning disability because just because they regress doesn't mean there's anything wrong cognitively.  It's also not a mental disability because regression is temporary.  Autism also is not correct because regression isn't a diagnosis such as that but rather a stage a toddler or small child may go through while developing.

I hope this helps!!!

the correct answer is d. sinking. - apex.