HSK C2/W2/V2
Correct

纸

/ zhǐ / 
Strokes

Definition

paper/classifier for documents, letter etc

Example

As a Noun
paper
1
Yī
一
zhāng
张
zhǐ
纸

a piece/sheet of paper

As a Measure word
[for letters, documents, etc]
2
Yī
一
zhǐ
纸
jìnlìng
禁令

a ban; an injunction

3
Yī
一
zhǐ
纸
gōngwén
公文

a document

4
Dānjù
单据
sān
三
zhǐ
纸

three bills