_ A string of length 90 cm is fastened to two points ‘A’ and ‘B’ at the same level 60 cm apart. A ring weighing 120 g is slided on the string. A horizontal force ‘P’ is applied to the ring such that it is in equilibrium vertically below ‘B’. The value of ‘P’ is:$?

• A. 40 g
• B. 60 g
• C. 80 g
• D. 100 g