This option shows
how you want to present your slide. You can choose from four options. Three are
presented by us and the other one is presented by your company/own individual
design. The slide options can look different than shown in this picture depending
on which question setting you are on.
Step 1: Create
Start by
creating your first slide in PowerPoint and then click "Add
Question".
Example:

Step 2: Locate
Locate the
slide you want to modify and click "Edit Question Settings". From
there, select the "Slide Design" tab.
Example:

Step 3: Select
Here
select one of the 4 options, if you decide you want your presentation to look
like your master slide please read the following article: How
does the master slide work?
Example:

*note: if you are
a user of a company that uses “full branding” you may also get an option to use
your own corporate identity style (color scheme and layout)
Step 4: Save
Once you've selected your desired
design, click "Save Settings". You can also choose to apply your
design choice to all of your slides by checking the "Apply to All"
option before saving your settings.
Example:

If all done correctly you should now be able to use the Slide design option!