What will happen to all HTML content with the class attribute "goodstuff" according to the provided CSS rule?

The correct answer reflects that all HTML elements with the class attribute "goodstuff" will be styled with specific formatting: bold text, a green color, and a font size of 14 pixels. This means that any text or content wrapped in an HTML element that includes the class "goodstuff" will visually stand out due to these modifications.

In CSS, class selectors are prefixed with a dot (.), and when you apply styles to a class, all elements with that class inherit those styles. Bold text is typically achieved using the font-weight property, green color can be set with the color property, and the size is determined using the font-size property. This combination of styles is effective for emphasizing content. Hence, the elements designated as "goodstuff" will not only be styled but will also present an identifiable visual cue to the user about the significance or relevance of that content.