What is a recommended step to restore the original list after checking for palindrome by reversing the second half?

• A. Reverse the first half again to restore.
• B. Do nothing.
• C. Attach a copy of the original list.
• D. Reverse the second half again to restore.

Answer: (D)

When you check a list for palindrome by reversing the second half, you temporarily alter the list to compare mirrored elements. To restore the original structure, reverse that second half again. Reversing a sequence twice brings it back to its starting order, so this undoes the initial modification and leaves the list unchanged. Reversing the first half would disrupt the original order there, doing nothing would leave the list in a modified state, and attaching a copy adds unnecessary overhead. Restoring by reversing the second half again is the clean, in-place way to return to the original list.