How can Dave prevent his changes from being lost due to a Git conflict during a specific promotion?

To prevent Dave's changes from being lost due to a Git conflict during a specific promotion, it's essential to manually promote and remove ApexClass from the Exclude From Auto Resolve multi-select picklist. This approach allows Dave to take control of how the conflict is managed since excluding certain components from auto-resolve means that they will not be instantiated during the promotion process, which can ultimately lead to losing or not incorporating his changes.

By manually promoting the ApexClass, Dave ensures that his specific changes are tracked and included in the deployment, rather than being overshadowed or ignored because of a default configuration that excludes it from auto-resolving conflicts. This is particularly important in a team environment where multiple developers may be working on similar components simultaneously, and having the flexibility to manage what is excluded helps safeguard against unintended overwrites or deletions of crucial code.

The other options involve either general practices that don't specifically address conflict management related to ApexClass or simply monitoring repository status, which does not influence how conflicts are resolved during the promotion. Hence, option B effectively aligns with the need for maintaining Dave's specific changes in the face of potential conflicts.