A particle of mass m moves in a circular orbit of radius r under in action of an attractive force \[\frac{-{{K}^{2}}}{{{r}^{2}}}\] which always acts towards the centre r of the orbit. What is the total energy in the particle?

• A. \[\frac{k}{{{r}^{2}}}\]
• B. \[\frac{2k}{r}\]
• C. \[\frac{{{k}^{2}}}{r}\]
• D. \[\frac{k}{2r}\]