Which of the following planar complex is diamagnetic and shows stereo isomerism?

Which cyano complex exhibits the minimum magnetic moment?

Which of the following compounds may show optical activity?

Observe the following complex ions:

Complex Ion	Label
$[Mn(CN)_6]^{3-}$	$A$
$[Fe(CN)_6]^{3-}$	$B$
$[CoF_6]^{3-}$	$C$
$[Co(C_2O_4)_3]^{3-}$	$D$

Identify the option in which the unpaired electrons in the complex ions are in correct increasing order.

An octahedral complex having molecular composition $Co \cdot 5NH_3 \cdot Cl \cdot SO_4$ has two isomers $A$ and $B$. The solution of $A$ gives a white precipitate with $AgNO_3$ solution and the solution of $B$ gives a white precipitate with $BaCl_2$ solution. The type of isomerism exhibited by the complex is,

$[Ti(H_2O)_6]^{3+}$ is paramagnetic in nature due to