**Question:** An eleven-month-old boy is all the time so restless that the rest of the class is unable to concentrate. He is hardly ever in his seat but roams around the hall. He has difficulty playing quietly. The most likely diagnosis is?

A. Attention Deficit Hyperactivity Disorder (ADHD)
B. Dyslexia
C. Autism Spectrum Disorder (ASD)
D. Intellectual Disability

**Correct Answer:** A. Attention Deficit Hyperactivity Disorder (ADHD)

**Core Concept:**
Attention Deficit Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder in childhood characterized by excessive restlessness, impulsivity, and hyperactivity. It can manifest in three subtypes: predominantly inattentive, predominantly hyperkinetic, and combined type.

**Why the Correct Answer is Right:**
In the given scenario, the child exhibits excessive restlessness and difficulty in concentration, being unable to sit still or play quietly. These symptoms align with the core characteristics of ADHD, which is characterized by inattention, hyperactivity, and impulsivity.

**Why Each Wrong Option is Incorrect:**

A. Dyslexia: This is a specific learning disorder characterized by difficulties with reading, spelling, and written language development. The symptoms described are not consistent with dyslexia.

B. Autism Spectrum Disorder (ASD): ASD is characterized by impairments in social interaction, communication, and repetitive and restricted behaviors. The symptoms described are not consistent with ASD.

C. Intellectual Disability: Intellectual disability refers to significantly reduced intelligence and adaptive functioning, which is not consistent with the presented symptoms.

**Clinical Pearl**: It is crucial to differentiate between ADHD and other conditions like dyslexia, ASD, and intellectual disability, as appropriate interventions and management strategies differ significantly for each condition. Early identification and intervention can significantly improve the child's quality of life, academic performance, and social interactions.