https://docs.microsoft.com/en-us/azure/virtual-machines/windows/managed-disks-overview#highly-durable-and-available

Highly durable and available

Managed disks are designed for 99.999% availability. Managed disks achieve this by providing you with three replicas of your data, allowing for high durability. If one or even two replicas experience issues, the remaining replicas help ensure persistence of your data and high tolerance against failures. 

from the docs 🙂

3 copies only but does support spreading those replicas across an Availability Zone where supported