Correct Answer - Option 4 : 19.92 m

**Concept:**

\(True\;length\;line = \frac{{l'}}{l} \times measured\;length\\ \)

**Calculation:**

True length of line (L) = 200 m

Actual length of chain (l) = 20 m

Measured length of line (L') = 200.80 m

Corrected length of chain (l') = ?

So, we know

\(True\;length\;line = \frac{{l'}}{l} \times measured\;length\\ \)

\(\Rightarrow 200 = \frac{{l'}}{{20}} \times 200.80\)

**∴ l' = 19.92 m**