Final answer:
Azure regions consist of multiple datacenters to ensure high availability and redundancy, not just one datacenter.
Step-by-step explanation:
The correct answer to the question about the number of datacenters in each Azure region is b) Multiple datacenters per region. Azure regions are large geographical areas that Microsoft has designated for its cloud services, and each region consists of multiple datacenters clustered close to each other. These clusters of datacenters are designed to ensure high availability and redundancy. This means that if one datacenter experiences issues, another can take over, thereby minimizing the risk of service disruptions for their customers.