Based on theFortinet NSE 7 - Public Cloud Security 7.4/7.6curriculum andAzure Resource Manager (ARM)deployment logic, the what-if tool provides a predictive analysis of infrastructure changes.

Analyzing the Modification Symbols (Option B):The exhibit shows several critical changes being attempted simultaneously on the ServerApps_vnet.

VNet Address Space Change:The symbol- (Delete)is next to the address space 10.0.0.0/16, and+ (Create)is next to 192.168.0.0/24.

Subnet Modification:Further down, the symbol~ (Modify)indicates an attempt to change the prefix of an existing subnet from 10.0.1.0/24 to 10.0.2.0/24.

Azure Deployment Constraints:According to theFortiOS 7.6 Azure Administration Guide, Azure networking has strict dependencies. Youcannot delete or modify an address spacethat contains active subnets or resources.

Why the deployment fails:The what-if output shows the administrator is trying to remove the 10.0.0.0/16 address range. However, the existing subnet 10.0.1.0/24 is still "resident" within that range during the transaction. Because the subnet is currently attached to the address space being deleted, Azure Resource Manager will reject the deployment as an invalid operation. The attempt to add a new 192.168.0.0/24 range does not resolve the conflict of removing the active range.

Why other options are incorrect:

Option A:The tool shows that 10.0.1.0/24 is beingchangedto 10.0.2.0/24, not that one is replacing the other as a new entity.

Option C:The symbols show amodification(~) of an existing subnet (index 0:), not thecreation(+) of an entirely new subnet.

Option D:The VNet name ServerApps_vnet is not being changed; only its internal properties (tags, address space, and subnets) are being modified.