___________________________ is a stimulant,and for most individuals it speeds up the nervous system and behavior.However,in many children with ADHD it has the opposite effect.

A) Activity drug
B) Caffeine
C) Ritalin
D) An antibiotic

Ritalin

A medication commonly prescribed to treat Attention Deficit Hyperactivity Disorder (ADHD) and narcolepsy, working by stimulating the central nervous system.

Stimulant

A substance that raises levels of physiological or nervous activity in the body, often used to enhance alertness, attention, and energy.

Nervous System

The complex network of nerves and cells that transmit signals between different parts of the body to coordinate bodily functions and responses.