Answer :
Slide master, because in this feature she is able to customize the theme, and layout of every slide in the Powerpoint presentation before she start adding content. The slide master is a feature used mostly if a user would like to create a template or when organizing how the content will flow through out the presentation. The tool is widely used by large corporations to create their template slides for any presentation made in the company, especially ones that are very keen to make their branding consistent.