Assertion(A): For long DNA molecules, replication occurs within the replication fork.
Reason(R): It takes a very high amount of energy to open the DNA along its full length.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.