Find the odd color (primary hue vs neutral): Choose the one that is not among the primary hues in the traditional RBY set.

Introduction / Context:
Color classification here follows the traditional art primaries: red, blue, and yellow are treated as primary hues. Black is a neutral (achromatic) color, not a hue on the color wheel, which cleanly separates it from the others.

Given Data / Assumptions:

• Red/Blue/Yellow: primary hues in many art/paint contexts.
• Black: neutral/achromatic; absence of light in additive sense, or a pigment mixture in subtractive use.

Concept / Approach:
Use color-wheel status (hue vs neutral). Primary hues serve as base for mixing many other colors; black does not act as a hue and sits off the wheel.

Step-by-Step Solution:

Verification / Alternative check:
On a standard color wheel, you will find red/blue/yellow positions but no position for black as a hue.

Why Other Options Are Wrong:
They share primary-hue status used for mixing palettes.

Common Pitfalls:
Do not mix additive (RGB) and subtractive (RYB/CMY) models; whichever model, black is not a hue.

Final Answer:
Black