The correct answer is D, because:

When using the "View As Web Page" (VAWP) link in Salesforce Marketing Cloud, it references a unique URL tied to the SendID and SubscriberKey.

If the original audience is overwritten (i.e., deleted and recreated), the SendID linked to the VAWP breaks, because the original context no longer exists.

To prevent this, upserting (inserting new and updating existing records) ensures that subscriber records persist and stay tied to the correct send, keeping the VAWP links functional even as the audience updates daily.

Official Salesforce documentation specifies:

"Overwriting a Data Extension can cause issues with Send Logging and View As Web Page links. If historical data must be maintained to ensure link functionality, records should be upserted rather than overwritten."

(Source: Salesforce Marketing Cloud Data Extensions Best Practices Guide)

In an upsert, you are updating existing records based on a primary key (typically SubscriberKey) and inserting new ones when no match exists, thus maintaining historical integrity necessary for things like VAWP.

Reference Extract:

"An upsert operation adds new records and updates existing ones in a Data Extension without deleting historical data. This method maintains the consistency required for links like 'View As Web Page' to remain functional."

(Source: Salesforce Marketing Cloud SQL Query Activities - Best Practices)

Why the other options are wrong:

A: Exclusion lists are about avoiding resending, not about preserving VAWP functionality.

B: AMPscript and send logging manage dynamic content, not VAWP link integrity.

C: Overwriting the DE deletes the old SendIDs, breaking VAWP links.

Thus, option D (Upsert) is correct.