Which of the following individuals is not eligible for military healthcare through the Department of Defense?

The correct answer is that individuals who have never served in the military are not eligible for military healthcare through the Department of Defense. Military healthcare programs, such as TRICARE, are designed specifically to provide medical benefits to those who have served in the armed forces and their eligible dependents.

Medal of Honor recipients and their dependents, active duty reserve component members, and widows and unmarried children under 26 are all included in the eligibility criteria for receiving military healthcare benefits. These groups have direct or indirect ties to military service, qualifying them for the healthcare programs offered by the Department of Defense. In contrast, individuals without any military service do not meet the necessary criteria to access these benefits.