Final answer:
The drop-down arrow that applies a different layout to a selected slide is called 'Layout Options'. It allows users to change the slide layout in presentation software, even if the slide already contains text or other content.
Step-by-step explanation:
The correct answer to the question is b) Layout Options. The Layout Options drop-down arrow allows you to apply a different layout to a selected slide in presentation software such as Microsoft PowerPoint. This feature can be particularly useful if you need to change the design or the structure of a slide to better present information, even if the slide has text or other content already in place. For example, you might have a slide with a basic title and content layout, but you realize that a two-column layout would present your points more effectively. Using the Layout Options feature, you can easily make this change without having to manually adjust the slide elements.