Final answer:
The United Kingdom has socialized medicine through the National Health Service (NHS).
Step-by-step explanation:
Socialized medicine refers to a system where the government owns and runs the healthcare system. Among the options given, the country that has socialized medicine is The United Kingdom (B). The United Kingdom operates the National Health Service (NHS), which provides free healthcare to all its residents. This is an example of socialized medicine, where the government owns and runs the healthcare infrastructure, employs healthcare professionals, and funds the system through taxes.