What HTML attribute is used to define inline styles?

The attribute that is utilized to define inline styles in HTML is the style attribute. This attribute allows you to apply CSS directly to an HTML element by embedding the CSS declarations inside the attribute.

For instance, using the style attribute enables you to set specific visual styles for that particular element, such as changing its color, font size, or margins without needing to create external or internal style sheets. This is especially useful for quick styling or for overriding styles specified in a stylesheet.

Using other attributes like class or id serves different purposes: the class attribute is used to apply styles defined in a CSS stylesheet that can be shared across multiple elements, while the id attribute provides a unique identifier for a specific element that can also be targeted with CSS or JavaScript. The format option is not a standard HTML attribute related to inline styles or CSS. Therefore, the style attribute is the most direct and effective way to implement inline styles for HTML elements.