By default, WHMCS does not allow dependencies between configurable options. If you have a product where the customer can configure the server himself, this can lead to invalid configurations (e.g. 2 disks + RAID 10).
We offer an additional module where dependencies between configurable options can be created. You can find more information here:
If you have any questions about the dependency module or you are not sure if it fits the purpose, feel free to contact our support.