The hybridisation of iron in ${\mathrm{K}}_4\left[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6\right]$ is
 

Given:

The hybridization of iron in  ${\mathrm{K}}_4\left[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6\right]$ is

Explanation:

• The cyanide ion CN  is the ligand in this instance and the coordination number of the iron is 6,
• The six cyanide ions will give their electron pair and bind to the two "3d" orbitals, one "4s" orbital, and three "4p" orbitals in front of them to create the complex.

Hence, the correct answer is (C) d²sp³.