The number of records out of union is less than intended. Which conclusion should be made?

A workflow has a scheduler and default error management.
What happens if an error occurs during a run?

For which reason does a fork activity produce an error?

Why might a Practitioner change the filtering dimension in a query?

A large clothing brand that has several thousand boutiques all over the US decides to create a special offer of 50% off all merchandise in their catalog. This offer is aimed at the best clients of the brand's US stores, meaning those who have spent more than S300 since the beginning of the year.
The business practitioner decides to use Distributed Marketing, which will allow selection of the stores' best clients (grouped by region). These selected clients will receive the email delivery containing the special offer.
What campaign template should the business practitioner use?