The answer is They are able to produce ATP molecules to help power metabolic processes

The endosymbiotic theory explains that mitochondria and chloroplasts descended from the same type of bacteria. According to the endosymbiotic theory, a host cell ingested symbiotic bacteria. The bacteria later specialised into mitochondria or chloroplasts. The evidence for this theory is that mitochondria and chloroplasts, similarly to bacteria, have their own circular DNA and replicate in a manner similar to some bacteria cells. they have a double membrane that resembles that of some ancient prokaryotic cells and their inner membranes contain the same enzymes as prokaryotic plasma membranes. 

However, chloroplasts do not produce ATP molecules, they are involved in the process of photosynthesis. On the other hand, mitochondria are able to produce ATP molecules to help power metabolic processes. So, this choice cannot be correct.