Which AWS CloudFormation asset specifies that a resource must wait to be created until after another resource has been created?

The correct answer is the DependsOn attribute. This attribute is specifically designed to create dependencies between resources in a CloudFormation template. When you define a resource with the DependsOn attribute, it instructs AWS CloudFormation to wait for the specified resource or resources to be successfully created before proceeding with the creation of the dependent resource.

This is particularly useful in scenarios where certain resources must be fully operational before others can be created. For example, if you have an Amazon RDS database instance that must be available before an EC2 instance that connects to it is launched, you would use the DependsOn attribute to ensure that the RDS instance is entirely provisioned and ready to use first.

This prevents errors that might arise from trying to create resources that rely on others being in place, streamlining stack creation and ensuring that all dependencies are handled correctly.

The other available attributes do not serve the same function: ResourcePolicy deals with permissions associated with a resource, Output attribute is used to specify outputs that are returned from a stack, and Condition attribute defines conditions under which certain resources are created or their properties are set, rather than managing the order of resource creation.