The answer is A. OCD and ADHD are the disorders that are most highly comorbid with Tourette’s syndrome. The combination of tics, OCD, and ADHD is called the “Tourette’s syndrome triad.” Tourette’s is viewed as a neuropsychiatric symptom disorder that co-occurs with symptoms of OCD and ADHD, although children may not always meet the full diagnostic criteria for all 3 conditions.

Publication reference : Kurlan, R. Clinical Practice. Tourette’s Syndrome. NEJM. 2010. 363(24): 2332-2338.
Reference URL: https://www.ncbi.nlm.nih.gov/pubmed/21142535