A square frame of ABCD consisting of five steel bars of cross section area 400 \[m{{m}^{2}}\] and joined by pivot is subjected to action of two forces \[P=40\text{ }kN\]in the direction of the diagonal as shown. Find change in angle at A if Young's modulus \[Y=2\times {{10}^{5}}N/\min \]

• A. \[\frac{1}{2000}rad\]
• B. \[\frac{1}{1000}rad\]
• C. \[\frac{\sqrt{2}}{1000}rad\]
• D. none