Which statements about change set deployments are accurate?

Change set deployments in Salesforce are a mechanism for packaging and transferring metadata from one Salesforce organization to another. The accurate statement among the provided choices is that they require a deployment connection. This is crucial because a deployment connection establishes a link between the source and target organizations, enabling the effective transfer of changes encapsulated in a change set.

Deployment connections allow for a secure and reliable way to manage how changes are deployed between related organizations, which typically includes production and sandbox environments. This linkage is essential for ensuring that the changes are correctly applied and monitored during the deployment process.

In addition, the all or none deployment model means that when a change set is deployed, it either succeeds entirely or fails completely, ensuring consistency in the metadata deployed. However, change sets cannot be used to transfer actual data records, such as Contact records, as they are designed solely for metadata transfer.

The correct understanding of these components clarifies how change set deployments function within the Salesforce ecosystem.