Below are two statements, one labeled as Assertion $(A)$ and the other as Reason $(R):$

Assertion $(A)$: Among group $13$ elements, boron's melting point is unusually high $(2453 \mathrm{~K})$.

Reason $(R):$ Solid boron has a strong crystalline lattice.

In the context of the above statements, choose the correct answer from the following options:

• A

  Both $A$ and $R$ are true, but $R$ is not the correct explanation of $A.$

   

   

• B

  Both $A$ and $R$ are true, but $R$ is the correct explanation of $A.$

• C

  $A $ is true, but $R$ is false

   

• D

  $A$ is false, but $R$ is true