The deformation of a vertically held bar of length L and cross-section A is due to its self-weight only. If Young’s modulus is E and the unit weight of the bar is γ, the elongation dL is

• A. \(\frac{{\gamma {L^3}}}{{2E}}\)
• B. \(\frac{{E{L^2}}}{{2\gamma }}\)
• C. \(\frac{{\gamma {L^2}}}{{2E}}\)
• D. \(\frac{{\gamma {L^2}}}{{2AE}}\)