A.\(\frac{{{\pi ^2}}}{{36}} - \frac{{\pi \sqrt 3 }}{3} + \ln 2\).
B.\(\frac{{4{\pi ^2}}}{9} - \frac{{\pi \sqrt 3 }}{3} - \ln 2\).
C.\(\frac{{4{\pi ^2}}}{9} - \frac{{\pi \sqrt 3 }}{3} + \ln 2\) .
D.\(\frac{{{\pi ^2}}}{{36}} - \frac{{\pi \sqrt 3 }}{3} - \ln 2\).