The $[\mathrm{Co}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6{]}^{2+}$ion has three unpaired electrons. The hybridization of Co in $[\mathrm{Co}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6{]}^{2+}$ is:

• A

  ${\mathrm{sp}}^3$

• B

  ${\mathrm{dsp}}^2$

• C

  ${\mathrm{sp}}^3{\mathrm{d}}^2$

• D

  ${\mathrm{d}}^2{\mathrm{sp}}^3$