Answer: The question is not complete, the options are not given.
But the correct answer is.
They are likely symbiotic with the dorminant species.
Step-by-step explanation:
A keystone species is a species which has disproportionately large effect on the communities it hold together by maintaining the biodiversity of the ecosystem and causing the abundance of other organisms present in the ecosystem. They play a role in the existence of species present in their environment.
The tree types of keystone species are predators, mutualist and ecosystem engineers.