Let each side be \(a\)
\(4a = 20\)
\(a = 5\)

Area of square \(= a^2 = 25\)

The diagonals in a square divide it in 4 equal Isosceles Right triangles
Therefore, Area of Shaded region \(= \frac{25}{4}\)

Col. A: \(5\)
Col. B: \(\frac{25}{4} = 6.25\)

Hence, option B

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