Main features of ADHD are ________________.

The correct answer is Option (4) → Inattention and Hyperactivity

Option (1) Low intelligence and inattention — Incorrect. Inattention is a feature of ADHD, but low intelligence is not. Below-average intellectual functioning, an IQ of about 70 or below with deficits in adaptive behaviour, marks intellectual disability, a different neurodevelopmental disorder.

Option (2) Lack of communication skills and low intelligence — Incorrect. Neither is a main feature of ADHD. Impairments in social interaction and communication skills mark autism spectrum disorder, and low intelligence marks intellectual disability.

Option (3) Inattention and lack of communication skills — Incorrect. The first half is right, but lack of communication skills belongs to autism spectrum disorder, not ADHD.

Option (4) Inattention and Hyperactivity — Correct. The two main features of ADHD are inattention and hyperactivity-impulsivity. Inattentive children find it hard to sustain mental effort, follow instructions or finish tasks; hyperactive children are in constant motion, fidget, squirm and run around aimlessly, and talk incessantly.