Two metallic spheres each of mass M are suspended by two strings each of length L. The distance between the upper ends of strings is L (the same as length of the two strings). The angle which the strings will make the vertical due to mutual attraction of the sphere is :
1) tan^-1[ GM / gL ]                        2) tan^-1 [ GM / 2gL ]                     3) tan^-1[ GM / gL² ]                     4) tan^-1 [ 2GM / gL²  ]