Troy, a six-year-old boy with autism, has received applied behavior analysis treatment for the past four years. Which of the following statements about Troy's current situation is most accurate?

Troy's treatment is relatively easy to implement, but his parents are thinking of dropping out because the treatment is so expensive.

Troy's cognitive skills have significantly improved, but he dislikes his treatment, so he has become defiant and difficult.

Troy is satisfied with his treatment and is a happier child, but his IQ is still low and he cannot be taught in normal classrooms at school.

Troy's treatment is very time-consuming and intense, but his IQ is now 20 points higher than when he started treatment.