When Luke was 17 years old,his intelligence test score was below 98 percent of all test-takers.Now at the age of 23,he needs adult supervision because he is not able to adapt to the normal demands of independent living.Luke most clearly meets the requirements for being assigned a diagnosis of

A) Down syndrome.
B) autism spectrum disorder.
C) intellectual disability.
D) savant syndrome.

Luke's low intelligence test score at age 17 and his current inability to adapt to independent living indicate intellectual disability, which is characterized by limitations in intellectual functioning and adaptive behaviors. Down syndrome, autism spectrum disorder, and savant syndrome may also involve intellectual disability, but the given information does not provide enough evidence to support a diagnosis of any of these specific conditions.