One end of a massless spring of spring constant $k$ and natural length $l_{0}$ is fixed,while the other end is connected to a small object of mass $m$ lying on a frictionless table. The spring remains horizontal on the table. If the object is made to rotate at an angular velocity $\omega$ about an axis passing through the fixed end,then the elongation of the spring will be

• A
  $\frac{k - m \omega^{2} l_{0}}{m \omega^{2}}$
• B
  $\frac{m \omega^{2} l_{0}}{k + m \omega^{2}}$
• C
  $\frac{m \omega^{2} l_{0}}{k - m \omega^{2}}$
• D
  $\frac{k + m \omega^{2} l_{0}}{m \omega^{2}}$