Assertion : In a $DNA$ molecule, $A-T$ rich parts melt before $G-C$ rich parts.

Reason : In between $A$ and $T$ there are three $H-$ bond, whereas in between $G$ and $C$ there are two $H-$ bonds.

• A

  If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

• B

  If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

• C

  If the Assertion is correct but Reason is incorrect.

• D

  If both the Assertion and Reason are incorrect.