Correct

国书

/ guóshū / 
Strokes

Definition

credentials (of a diplomat)/documents exchanged between nations/national or dynastic history book

Example

As a Noun

letter of credence; credentials

1
Jiēshòu
接受
guóshū
国书

accept credentials

2
Dìjiāo
递交
guóshū
国书

present one's credentials