Which of the following substances has the least covalent character?

Which of the following statements are correct?
$(A)$ Both $LiCl$ and $MgCl_2$ are soluble in ethanol.
$(B)$ The oxides $Li_2O$ and $MgO$ combine with excess of oxygen to give superoxide.
$(C)$ $LiF$ is less soluble in water than other alkali metal fluorides.
$(D)$ $Li_2O$ is more soluble in water than other alkali metal oxides.
Choose the most appropriate answer from the options given below.

Which one is least ionic in the following compounds?

The covalent character of $CaCl_2, BaCl_2, SrCl_2$ and $MgCl_2$ follows the order:

Which of the following orders is correct when arranged in increasing order of ionic character?

The correct increasing order of polarising power is