The correct answer is option 'C' - Ctrl click each slide.

Explanation:
To select more than one slide in a presentation, you can use the Ctrl key in combination with the mouse click. This allows you to choose multiple slides simultaneously.

Here is a step-by-step explanation of how to select more than one slide in a presentation using the Ctrl key:

1. Open the presentation:
- Launch the presentation software, such as Microsoft PowerPoint or Google Slides.
- Open the desired presentation file.

2. Navigate to the slide pane:
- Locate the slide pane within the presentation software.
- The slide pane typically appears on the left side of the screen and displays a thumbnail view of all the slides in the presentation.

3. Select the first slide:
- Click on the thumbnail of the first slide that you want to select.
- This slide will be the starting point for the selection.

4. Hold the Ctrl key:
- While keeping the Ctrl key on your keyboard pressed, move on to the next slide you want to select.

5. Click on the additional slides:
- With the Ctrl key still held down, click on the thumbnails of the additional slides you want to select.
- Each click will add the respective slide to the selection.

6. Release the Ctrl key:
- Once you have selected all the slides you need, release the Ctrl key on your keyboard.

By following these steps, you can easily select multiple slides in a presentation using the Ctrl key. This shortcut is useful when you want to apply formatting changes, animations, or transitions to multiple slides at once. It saves time and effort compared to individually selecting each slide using other methods like Shift-click or Shift-drag.