Assertion $(A)$: Transition elements have higher enthalpies of atomization.
Reason $(R)$: Large number of unpaired electrons present in transition elements facilitate strong interatomic interaction and strong bonding between atoms.

• A
  Both $(A)$ and $(R)$ are correct and $(R)$ is the correct explanation of $(A)$.
• B
  Both $(A)$ and $(R)$ are correct and $(R)$ is not the correct explanation of $(A)$.
• C
  $(A)$ is correct and $(R)$ is incorrect.
• D
  $(A)$ is incorrect and $(R)$ is correct.