# The primary valency of 'Fe' in complex $K_4[Fe(CN)_6]$ is

$(a)\;2\qquad(b)\;3\qquad(c)\;6\qquad(d)\;4$

The primary valency of 'Fe' in complex $K_4[Fe(CN)_6]$ is 2.
Hence (a) is the correct answer.