Answer:
Mutualistic relationship
Step-by-step explanation:
A symbiotic relationship is defined as the close and long-term biological relationship between two different organisms for example : parasitic., mutualistic, or commensalism.
Ants and acacia trees have a mutualistic association because trees provide food and shelter to the ants and in return ants protect trees from other herbivores.
Hence, the correct answer is "Mutualistic relationship".