I run the SEO of a pretty big site and due to some product changes the homepage will show the exact content of one of the sub directories. For example: mysite.com/cat/cat/ instead of mysite.com

I must say that most the site's impressions come from the homepage.

How would you proceed in this situation?

A. redirect the homepage to the sub directory?
B. Redirect the sub directory to the homepage? (makes less sense in terms of the product)
C. Leave both and have a canonical from the sub directory to the homepage?

I'm interested to know what you guys think.

Thanks