Paulinella Chromatophora Is One of the Few Cercozoans That Is

Paulinella chromatophora is one of the few cercozoans that is autotrophic, carrying out aerobic photosynthesis with its two elongated "chromatophores." The chromatophores are contained within vesicles of the host cell, and each is derived from a cyanobacterium, though not the same type of cyanobacterium that gave rise to the chloroplasts of algae and plants.
Which of the following results would be most important in determining whether the chromatophore of P. chromatophora is still an endosymbiont, or is an organelle, as the term chromatophore implies?

A) if P. chromatophora is less fit without its chromatophore than with it
B) if the chromatophore is less fit without the host cercozoan than with it
C) if there is ongoing metabolic cooperation between the chromatophore and the host cercozoan
D) if there has been movement of genes from the chromatophore genome to the nuclear genome, such that these genes are no longer present in the chromatophore genome