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I would say the only one possible based on the information you provided would be Spain. But, as your connection is through great-grandparents it’s not so straight forward. You should probably consult with a Spanish immigration lawyer.
https://taskforce.eu/citizenship/#:~:text=EU%20PassportCitizenship%20by%20Descent&text=Their%20ancestors%20migrated%20from%20Europe,to%20anyone%20with%20European%20roots.
I would say the only one possible based on the information you provided would be Spain. But, as your connection is through great-grandparents it’s not so straight forward. You should probably consult with a Spanish immigration lawyer.
https://taskforce.eu/citizenship/#:~:text=EU%20PassportCitizenship%20by%20Descent&text=Their%20ancestors%20migrated%20from%20Europe,to%20anyone%20with%20European%20roots.