Only show one category in my meta data for the front page

Code from the codex

I have used the above code to display the categories under each post on my front page.

The problem is, I only want to show the first category. How do I exclude a category using this code?

So for example, I have a post that has been added to a ‘slider’ category and a “style” category.

On the front page of my blog, I only want it to say / show the slider category

Can anyone point me in the right direction to make this work?

Thanks you