Which of the following compounds contains a covalent bond?

Which among the following is the correct decreasing order of covalent character of ionic bonds?

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R.$
Assertion $A :$ Lithium halides are somewhat covalent in nature.
Reason $R :$ Lithium possesses high polarization capability.
In the light of the above statements,choose the most appropriate answer from the options given below:

$A$ bond with maximum covalent character between non-metallic elements is formed:

Which of the following is a covalent compound?

$A$ metal,$M$,forms chlorides in its $+2$ and $+4$ oxidation states. Which of the following statements about these chlorides is correct?