Auto Scaling is a management service that can automatically adjust elastic computing resources based on your business ne

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Auto Scaling is a management service that can automatically adjust elastic computing resources based on your business needs and policies. It supports adding an existing ECS instance into the scaling group but imposes certain requirements on instance region. In this case, which of the following statements is true?

A. The instance and the scaling group must be in the same region but not necessarily the same zone.
B. The instance and the scaling group must be in the same region and zone.
C. The instance and the scaling group can be in different regions and zones.
D. Each scaling group can span up to two regions. After adding the ECS instance, the number of regions of all the ECS instances in the scaling group must be no greater than two.