Given below are two statements: One is labelled as Assertion $\mathrm{A}$ and the other labelled as Reason $\mathrm{R}.$
Assertion $\mathrm{A}$ : Lithium halides are some what covalent in nature.

Reason $\mathrm{R}$ : Lithium possess high polarisation capability.

In the light of the above statements, choose the most appropriate answer from the options given below:

• A

  $\mathrm{A}$ is true but $\mathrm{R}$ is false
• B

  $\mathrm{A}$ is false but $\mathrm{R}$ is true
• C

  Both $\mathrm{A}$ and $\mathrm{R}$ are true but $\mathrm{R}$ is NOT the correct explanation of $\mathrm{A}$
• Correct answer
  D

  Both $\mathrm{A}$ and $\mathrm{R}$ are true and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$

Hence, the correct answer is option: 'D'.