This is a fairly simple question that you can answer with the process of elimination.
A competitive relationship is a relationship between members of the same or different species in which individuals are adversely affected by those having the same living requirements, such as food or space.
A commensalistic relationship is a relationship between two different species where one species enjoys a benefit and the other isn't significantly affected.
A mutalistic relationship is a relationship between two different species where both species receive a benefit from the other.
A parasitic relationship is a relationship between two different species where the parasite (symbiont) benefits from the host and the host is harmed.
Hope this helps!
