A/B Test -> Variation B should not be indexed / robots=noindex

[dgent]

At Google is my SERP "Need help ... -> click here".
The user is directed to Variation-A.

I want the same Content but different layout (Variation-B)

So when the user clicks on "Need help" Google will separate the traffic to Variation-A and Variation-B.
But I do not want, that Variation-B (same Content) will be index.

Any idea?

Google won't do that. Simply run your whole site in the new layout for a month or two and see if sales increase or decline