Two small spheres each carrying a charge \[q\] are placed \[r\] metre apart. If one of the spheres is taken around the other one in a circular path of radius \[r\], the work done will be equal to [CPMT 1975, 91, 2001; NCERT 1980, 83; EAMCET 1994; MP PET 1995; MNR 1998; Pb. PMT 2000]

• A.                                                      Force between them \[\times \,r\]
• B.                    Force between them \[\times \,2\pi r\]
• C.                    Force between them \[/2\pi r\]
• D.                    Zero