question: As shown in the figure, the fixed straight rod at the left end is subjected to a torsion couple, and the torque at sections 1-1 and 2-2 is: <image 1>
  Options: A: 12.0kN.m, -3kN.m, B: -2.5kN.m, -3kN.m, C: -2.5kN.m, -3kN.m, D: 2.5kN.m, -3kN.m