A rigid cross-shaped arrangement with four arms PO, SO, QO and RO, each measuring $1.00\,\text{m}$ in length, is hinged at O. As illustrated, forces act at the ends of the arms and at the midpoints of the arms. What is the magnitude of the resultant moment on the structure about O?
- A$45\,\text{N m}$
- B$90\,\text{N m}$
- C$120\,\text{N m}$
- D$190\,\text{N m}$