It is called the Mediastinum. It is a membranous broad compartment of the thoracic cavity normally between body cavities or two parts of an organ for example between the lungs.. It contains the heart and together with the vessels, the esophagus, phrenic and cardiac nerves, trachea, thymus and the lymph nodes of the central chest.
This is a case of mitochondrial heredity so correct answer is e. Mitochondrial
In this case, the mother transfers her mitochondria to her children. So the child is affected. The male does not pass this trait on to his children.
We can see from the lineage that the mother has defective mitochondria so all their children will have defective mitochondria. One of his sons has mitochondrial, but is unable to pass it on to the next generation.