When writing a script that depends on a particular component, which attribute should be added?

The correct choice is the attribute that ensures a specified component is attached to the GameObject that the script is attached to. This attribute helps maintain the integrity of your scripts by informing Unity's editor to automatically add the required component if it’s missing. By using this attribute, you ensure that any script that relies on that specific component won't break due to the absence of the required functionality. This enhances user experience by preventing runtime errors and guiding developers during the setup process in the Unity editor.

The other options may sound plausible, but they do not serve the same purpose as the correct answer. For instance, the AddComponent option suggests directly adding components via code rather than enforcing their presence at the editor level. MandatoryComponent and ComponentDependency do not exist in Unity's attribute system, which means they wouldn't be functional or recognized by the Unity engine. Thus, using the RequireComponent attribute is both a best practice for ensuring component dependencies and a straightforward solution for maintaining script reliability.