How do u get first

You just made my day

It is correct. Why did you post this?

Maybe Doctor Wang married a Chinese person whose last name is Wang, and changed their last name.

Try doing Japanese to English, now THAT is hard to do

What would you expect to put? What did you put for your entire answer?

how else do you know which doctor you're talking about if you don't include his name?

By custom, that's how it's been done for any writing system outside of the Latin alphabets. Even François gets turned into Francis.

Report it as also correct.

In English the abbreviation for doctor requires a period or full stop Dr. Wang. I don’t know if Duolingo accepts the abbreviation though.

You are onto something here, but it's a bit more roundabout. 王King>玉Jade>国Nation. Jade was used in a lot of the royal artifacts and was regarded as a precious material, so it makes sense why it would be written as a king with a little artifact on him, and a jade artifact encased in a box would represent the nation. Interestingly though this is a result of Chinese simplification. The traditional way of writing 国 is 國, which is "or" in a box.