$[Co(NH_3)Cl(en)_2]^{2+}$ shows two geometrical isomers,$cis$ and $trans$. Which of the following statements is correct?

The type of isomerism present in pentaammine nitro chromium$(III)$ chloride is

The number of possible optical isomers for the complexes $MA_{2}B_{2}$ with $sp^{3}$ and $dsp^{2}$ hybridised metal atom,respectively,is.
Note : $A$ and $B$ are unidentate neutral and unidentate monoanionic ligands,respectively.

Total number of geometrical isomers possible for the complexes $[NiCl_4]^{2-}$,$[CoCl_2(NH_3)_4]^{+}$,$[Co(NH_3)_3(NO_2)_3]$ and $[Co(NH_3)_5Cl]^{2+}$ is

Given below are two statements,one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A:$ The spin only magnetic moment value for $[Fe(CN)_6]^{3-}$ is $1.74 \ BM$,whereas for $[Fe(H_2O)_6]^{3+}$ is $5.92 \ BM$.
Reason $R:$ In both complexes,$Fe$ is present in $+3$ oxidation state.
In the light of the above statements,choose the correct answer from the options given below:

The complex(es),which can exhibit the type of isomerism shown by $[Pt(NH_3)_2 Br_2]$,is(are) [en $= H_2 NCH_2 CH_2 NH_2$ ]
$(A)$ $[Pt(en)(SCN)_2]$
$(B)$ $[Zn(NH_3)_2 Cl_2]$
$(C)$ $[Pt(NH_3)_2 Cl_4]$
$(D)$ $[Cr(en)_2(H_2 O)(SO_4)]^{+}$