What type of hybridization is involved in $[Fe(CN)_6]^{3-}$?

The Jahn-Teller effect is not observed in high spin complexes of:

Which of the following statements is incorrect for the complex $[Cr(NH_3)_6]Cl_3$?

Identify the geometry of the complex formed when cobalt chloride is dissolved in water.

Given below are two statements :
Statement $I$: $[Ni(CN)_4]^{2-}$ is square planar and diamagnetic complex with $dsp^2$ hybridization for $Ni$ but $[Ni(CO)_4]$ is tetrahedral,diamagnetic and with $sp^3$ hybridization for $Ni$.
Statement $II$: $[NiCl_4]^{2-}$ and $[Ni(CO)_4]$ both have same $d$-electron configuration,have same geometry and are paramagnetic.
In light of the above statements,choose the correct answer from the options given below:

In the $Cu$-ammonia complex,the state of hybridization of $Cu^{2+}$ is: