Two things "that are" or "that is" another thing
In the following sentence:
It was tasteful – not boastful – but sent the clear message about the industry leader and gold standard that is Acme.
Should that bolded word be "is" or "are"?
Solution 1:
Based on @HotLicks instructive comments (thank you!), since it's a singular subject, the correct word choice would be is.