I am going to have to go with C. The reasoning behind this is because the question says "all-flash". For a Hybrid VSAN configuration, you can include other traffic. However, for an all-flash VSAN config, it states a 10GbE+ connection as it may consume higher bandwidth for higher throughput. (See below)
https://core.vmware.com/resource/vmware-vsan-design-guide#section4
In vSAN hybrid configurations, VMware supports 1Gb, 10Gb, 25Gb, 40Gb, and 100Gb Network Interface Cards (NICs) for vSAN network traffic. If a 1Gb NIC is used, VMware requires that this NIC is dedicated to vSAN traffic. If a 10Gb or higher bandwidth NICs are used, these can be shared with other network traffic types. While VMware has successfully run smaller hybrid vSAN deployments over 1Gb, the best practice is to use 10Gb links.
vSAN all-flash configurations are only supported with a 10Gb or higher connections. One reason for this is that the improved performance with an all-flash configuration may consume more network bandwidth between the hosts to gain higher throughput.