C. Slide Master
Selecting a theme ensures a consistent look across all your slides. However, even themes that seem to be a perfect match for your presentation may need some customizing.
After selecting a theme, click Slide Master on the View tab to edit the Slide Master and layouts. A Slide Master controls the look of all your slides. For example, changing the background styles, colors, fonts, or effects for the Slide Master affects every layout. Edits to a layout affect only that slide type. For example, if you add a company logo to the title slide, it will appear on every title slide in your presentation. If you want to edit objects on the Slide Master and layouts, use the Drawing Tools Format tab.