The possible reason for this situation is that only rate-based pricing cards are applied with VMC resources. A rate-based pricing card is a pricing card that defines the rates for each resource type, such as CPU, memory, disk, and network. A cost-based pricing card is a pricing card that defines the basic charges for each object type, such as host, cluster, datastore, and virtual machine. vRealize Operations supports both types of pricing cards for vSphere resources, but only supports rate-based pricing cards for VMC resources1. When a cost-based pricing card is assigned to a VMC resource, the price calculated for the policy is reported as zero2. To avoid this situation, the administrator should create and assign a rate-based pricing card for the VMC resource.

The other options are not correct, because they are not the possible reasons for this situation. Option A is not correct, because a zero value for one of the basic charges in the cost-based pricing card would not result in a zero price for the VM. The price of the VM would be calculated based on the sum of the basic charges for the VM object type and its parent object types, such as datastore, cluster, and host3. Option C is not correct, because the cost calculation does not need to run twice when using VMC. The cost calculation runs every 24 hours for all the pricing cards, regardless of the cloud provider4. Option D is not correct, because pricing cards are supported with VMC resources, as long as they are rate-based pricing cards1.

References:

Pricing for vRealize Automation 8.x Components in vRealize Operations - VMware Docs

Pricing Overview - VMware Docs

Add New Pricing Card - VMware Docs

Cost Calculation - VMware Docs