The correct answer is C. Slide master.
The slide master is a template that contains the basic design elements for all the slides in a presentation. This includes the background, fonts, colors, and any other objects that you want to appear on every slide. If you insert your logo on the slide master, it will appear on every slide in your presentation.
The handout master and notes master are also templates, but they are used to create handouts and notes, respectively. The handout master contains the design elements for the handouts, such as the page size and layout. The notes master contains the design elements for the speaker notes, such as the font and size of the text.
If you insert your logo on the handout master or notes master, it will appear on every handout or note that you create. However, it will not appear on the slides in your presentation.
Therefore, the correct answer is C. Slide master.