Final answer:
The predefined arrangements of slides in PowerPoint are known as Slide Layouts, which aid instructors in building lectures with a structured and appealing design.
Step-by-step explanation:
The name for PowerPoint's predefined slide arrangements is b) Slide Layouts. PowerPoint lecture slides are designed to be a starting point for instructors to build their lectures, providing essential outlines, images, and an overview of chapter topics. The predefined slide layouts help in organizing content on a slide in a visually appealing and consistent manner, allowing for a variety of content such as text, pictures, and charts to be effectively displayed.