On a fairly cool rainy day when the temperature is 20˚C, the length of a steel rail road track is 20cm. What will be its length on a hot dry day when the temperature is \(40^{\circ} \mathrm{C}\) ?

[Coefficient of linear exjpression of steel \(\left.=11 \times 10^{-6} \mathrm{~K}^{-1} \right]\)

A. \(20.009 \mathrm{~m}\)
B. \(20.004 \mathrm{~m}\)  
C. \(20.013 \mathrm{~m}\)
D. \(20.002 \mathrm{~m}\)

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Correct Answer: B