Which of the following group of concurrent forces may be in equilibrium (R=0)?

Options

A. `{:(A,B,C),(10,20,40):}`
B. `{:(A,B,C),(3,5,1):}`
C. `{:(A,B,C),(20,20,20):}`
D. `{:(A,B,C),(40,30,5):}`

Answer

C