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The storage account used for Azure virtual machine boot diagnostics must be a standard-performance-tier account, since Microsoft documents that attempting to use a premium storage account for boot diagnostics returns a StorageAccountTypeNotSupported error when the virtual machine is started, and it also cannot use zone-redundant storage, since ZRS is likewise unsupported for this specific resource and produces the same class of error. Looking at the four accounts in the table, storage3 and storage4 are both Premium-tier accounts, which immediately rules both of them out regardless of their redundancy setting, and storage2, despite being Standard tier, uses zone-redundant storage, which independently rules it out as well. That leaves storage1, which is both Standard performance tier and uses geo-redundant storage rather than zone-redundant storage, satisfying both documented requirements simultaneously. Because storage1 is the only one of the four accounts that avoids both the premium-tier restriction and the ZRS restriction at the same time, it is the only valid choice among the options offered for configuring VM1 ' s boot diagnostics storage.