The condition for a uniform spherical mass m of radius r to be a black hole is [G= gravitational constant and g= acceleration due to gravity]

• A

  ${(2\mathrm{Gm}/\mathrm{r})}^{1/2}\le \mathrm{c}$

• B

  ${(2\mathrm{Gm}/\mathrm{r})}^{1/2}=\mathrm{c}$

• C

  ${(2\mathrm{Gm}/\mathrm{r})}^{1/2}\ge \mathrm{c}$

• D

  ${(\mathrm{gm}/\mathrm{r})}^{1/2}\ge \mathrm{c}$