Your company has a DevOps team to manage AWS accounts used by all the other teams within the company. In the master AWS account, several CloudWatch Events Rules are established where the CloudWatch Events happening in other AWS accounts can be sent to. In order to do this, permissions have been configured in the default CloudWatch Event Bus of the master account in region ap-southeast-2. Which entities can be added so that they are permitted to send events to CloudWatch Event Bus in the master account? (Select TWO.) 

Answer options:

A.Certain IAM users in the same AWS Organization.
B.Another AWS Organization.
C.Everybody (all AWS accounts).
D.An AWS account which creates a CloudWatch Events rule in region ap-south-1 and sends events to the master account.
E.IAM groups.

Correct Answer – B, C
Please refer to
https://docs.aws.amazon.com/AmazonCloudWatch/latest/events/CloudWatchEvents-CrossAccountEventDelivery.html
for the details of sending and receiving CloudWatch Events between AWS Accounts.
Option A is incorrect: Because only individual AWS accounts or organizations can be granted access. 
Option B is CORRECT: Because when an organization is specified, all accounts in the organization are permitted.
Option C is CORRECT: Because Everybody can be selected which includes all accounts:
Option D is incorrect: Because the sender and receiver should belong to the same region. Refer to the above link.
Option E is incorrect: Similar to
Option A. IAM group is invalid.