There isn't one.
No US state has a capital of three letters unless you abbreviate Utah's capital, Salt Lake City to SLC
No state capital has a total of three letters or just three letters.
The capital that has only 3 letters is "Rome" which is the capital of Italy.
The only state capital that shares no letters with the state it is capital of is Oklahoma City, Oklahoma.
These letters (when capital) are the ones drawn with only straight lines. The other letters (again, when capital) are drawn with curves.
lid
The Hebrew alphabet doesn't have capital letters or lowercase letters. There is only one set of letters:Angel = מלאך (mal'akh)
You use capital letters only if it is a place. Also you use it to capitalize your first word of a sentence.
The flower with only three letters in its name is the "lily."
So you can read it
The capital of Guinea is Conakry. It's the only capital of Guinea.
London L O N