What is the best virus protection for my Mac?

None !!

There are no known Viruses in the wild that self replicate and affect macOS. There are Malware and Adware that does affect macOS and are often times downloaded as part of an Application from Third Party UnTrusted Site and get installed along with the Application.

And as @Niel has directed to use a Well Respected Contributor and Developer application for just that purpose Malware and Adware which are often times downloaded as part of an Application from Third Party UnTrusted Site and get installed along with the Application.

The defenses built into the OS, unless you're concerned about Windows malware. If you need a tool, click here.

(204076)