Here is what I did :
Considered that no force will be acting along the arcs.
Then calculated the Torques acting on the radially directed current elements about the point of emergence of long wire , say O, .
Then since they were acting like a couple, then I concluded that for a couple , torque acting is same about any point , so torque acting on that couple would be equal to the torque acting on the loop as only these forces account for the rotation of the loop,
Pls verify of my thought process was correct or I did a mistake and torque on the loop is incalculable from the information , Thanks in advance.