Which of the following has the lowest melting point?

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.

The correct order of increasing ionic character is:

The correct order of polarising power is:

Which is the correct order of covalent nature?

The compound with more covalent character in the following is