The equation ${\cos }^{-1}\sqrt{\frac{\mathrm{\alpha }-\mathrm{\theta }}{\mathrm{\alpha }-\mathrm{\beta }}}={\sin }^{-1}\sqrt{\frac{\mathrm{\theta }-\mathrm{\beta }}{\mathrm{\alpha }-\mathrm{\beta }}}$ is valid for

• A

  α > β and θ takes any value

• B

  α = θ = β

• C

  α > θ > β or α < θ < β

• D

  none of these.