The correct answer is: C. A slide master and title master for a specific design template.
A slide master is a template that contains the design elements that appear on all slides in a presentation, such as the background, fonts, and placeholders. A title master is a template that contains the design elements that appear on the title slide of a presentation, such as the title and subtitle placeholders. A slide-title master pair is a set of two masters, a slide master and a title master, that are used together to create a presentation.
Option A is incorrect because the title area and text area are part of a slide, not a slide-title master pair.
Option B is incorrect because a slide master and title master are not merged into a single slide. They are two separate masters that are used together to create a presentation.
Option D is incorrect because not all slide-title master pairs are for a specific design template. Some slide-title master pairs are used to create presentations that do not have a specific design template.