A user uses CloudFormation to launch an EC2 instance and plans to configure an application after the instance is launched. The user wants to coordinate stack resource creation with configuration actions that are external to the stack creation. How can the user configure this?

Answer options:

A.It is not possible that the stack creation will wait until one service is created and launched.
B.The user can use the HoldCondition resource to wait for the creation of the other dependent resources.
C.The user can use the DependentCondition resource to hold the creation of the other dependent resources.
D.Associate a CreationPolicy attribute with the wait condition.

Answer – D
You can use a wait condition for situations like the following.
To coordinate stack resource creation with configuration actions that are external to the stack creation.
To track the status of a configuration process.
For more information on Cloudformation Wait condition, please visit the link
http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-waitcondition.html