Duplicates/3x contacts

Hi,

I'm trying to clean and organize my contact list because I have duplicates, sometimes three times the same contact.

I followed the steps on Apple website.:

Remove duplicate contacts

Follow the steps for your operating system.

On your Mac

1. Make a copy of your contacts.
2. Open Contacts.
3. From the Card menu, select Card > Look for Duplicates.

However, I don't have the option "Select Card" Under Card, I just have the options "Export Group vCard" and "send email to card".

Please, does anyone have ideas? This endless list is driving me crazy.

With gratitude,

Sheila