Identify the complex which exhibits optical isomerism.

In an experiment,$m$ grams of a compound $X$ (gas/liquid/solid) taken in a container is loaded in a balance as shown in figure $I$ below. In the presence of a magnetic field,the pan with $X$ is either deflected upwards (figure $II$),or deflected downwards (figure $III$),depending on the compound $X$. Identify the correct statement$(s)$:
$(A)$ If $X$ is $H_2O_{(l)}$,deflection of the pan is upwards.
$(B)$ If $X$ is $K_4[Fe(CN)_6]_{(s)}$,deflection of the pan is upwards.
$(C)$ If $X$ is $O_{2(g)}$,deflection of the pan is downwards.
$(D)$ If $X$ is $C_6H_{6(l)}$,deflection of the pan is downwards.

In which of the following complex species,$\Delta_0 > P$ (pairing energy) with magnetic moment $\sqrt{3} \ B.M.$?

Which one has the highest paramagnetism?

Magnetic moment $2.83 \ BM$ is given by which of the following ions?
(At. nos. $Ti = 22, Cr = 24, Mn = 25, Ni = 28$)

Select the paramagnetic molecule$(s)$ from the following: