Final answer:
The likely diagnosis for a patient presenting with a widened mediastinum, a large left-sided hemothorax, and deviation of the mediastinum to the right is Aortic dissection.
Step-by-step explanation:
The likely diagnosis for a patient presenting with a widened mediastinum, a large left-sided hemothorax, and deviation of the mediastinum to the right is C) Aortic dissection. Aortic dissection is a life-threatening condition where there is a tear in the inner layer of the aorta, leading to blood flowing between the layers of the vessel wall. This can result in widening of the mediastinum, hemothorax, and deviation of the mediastinum.