Final answer:
Errors kill hundreds of thousands of people in U.S. hospitals annually.
Step-by-step explanation:
The findings of two major studies indicate that errors kill hundreds of thousands of people in U.S. hospitals annually.
One study revealed that around 98,000 deaths occur each year due to medical errors, while another study estimated the number to be around 250,000 deaths per year.
Therefore, the correct answer is c) Tens of Thousands.