Which of the following statements are true about the magnetic susceptibility ${\chi _m}$ of a paramagnetic substance?

• A
  Value of ${\chi _m}$ is inversely proportional to the absolute temperature of the sample.
• B
  ${\chi _m}$ is positive at all temperatures.
• C
  Both $(a)$ and $(b)$.
• D
  ${\chi _m}$ does not depend on the temperature of the sample.