The correct answer is: A. Placeholders.
Placeholders are objects on the slide that hold text. They are usually represented by a box with a dashed line border. Placeholders can be used to add text, tables, charts, images, and other objects to a slide.
Option B, object holders, is incorrect because object holders are not specific to text. They can hold any type of object, including text, images, charts, and tables.
Option C, auto layout, is incorrect because auto layout is a feature that allows you to create a slide with a specific layout. It does not refer to specific objects on the slide.
Option D, text holders, is incorrect because text holders is not a standard term used in PowerPoint.