What are the best antivirus options for iPhones?

No such product is required for your iPhone.

Don’t jailbreak your phone.

There are no known viruses in the wild that can infect an iphone that has not been jailbroken.

Apps and data on the phone are sandboxed. Not only does this prevent any would be viruses or malicious apps from accessing or damaging any other apps or data on the device, it effectively makes it impossible for antivirus software to do what it is advertised to do as well.

There is none needed and none that will offer any protection.

Installing antivirus software is a known issue for any financial apps or financial services you hope to use on your iPhone.