Which would be the most appropriate type of document for the situation

Could someone me with this question?

Which statement contains an opinion? the ants serve to protect the acacia from other plants and herbivores. the acacia depends on pollinators for the exchange of genetic material. the acacia has no chemical defenses to discourage herbivores. the ants provide the acacia with the best protection from other plants and herbivores.

Someone get back to me , i really don’t get this