Human Cells Contain Mitochondria,which Are Responsible for Processing the Energy

Human cells contain mitochondria,which are responsible for processing the energy needed by our cells.Remember that the ancestors of mitochondria may once have been free-living prokaryotes.If mitochondria were still considered separate organisms within human cells,which of the following would best describe the relationship with them?

A) parasitic
B) mutualistic
C) competitive
D) pathogenic