The strongest $P-O$ bond is found in the molecule

Which of the following options is correct with respect to bonds/forces of attraction?

Compare $\pi$-bond strength between $B$ and $N$ in the following compounds: $(I)$ $((CH_3)_3Si)_2N^{-}BH_2$ and $(II)$ $((CH_3)_3C)_2N^{-}BH_2$.

Arrange the following species in the increasing order of lone pairs of electrons:
$(A)$ $CO$
$(B)$ $NO_2^-$
$(C)$ $NF_3$
$(D)$ $CO_3^{2-}$

Identify the correct thermal stability orders among the following:
$(a) BeSO_4 < MgSO_4 < CaSO_4 < SrSO_4 < BaSO_4$
$(b) HF > H_2O > NH_3 > CH_4$
$(c) NH_3 > PH_3 > AsH_3 > SbH_3$
$(d) LiCl > BeCl_2 > BCl_3 > CCl_4$
$(e) Na_2CO_3 > MgCO_3 > Al_2(CO_3)_3$
$(f) Li_2CO_3 < Na_2CO_3 < K_2CO_3 < Rb_2CO_3 < Cs_2CO_3$

In which of the following compounds is the octet complete $(C)$ or incomplete $(IC)$ for all atoms?
$Al_2Cl_6$ $-$ $Al_2(CH_3)_6$ $-$ $AlF_3$ $-$ Dimer of $BeCl_2$ $-$ Dimer of $BeH_2$
(Note: $C$ for complete octet and $IC$ for incomplete octet.)