Explanation:

The Hyper-V networking section of the Administering Windows Server Hybrid Core Infrastructure material explains that Hyper-V provides three virtual switch types: External, Internal, and Private. It states:
"An External switch is bound to a physical NIC and can optionally connect the management OS; an Internal switch connects VMs to each other and to the host only; a Private switch connects VMs to each other only (no host access)." The guide further clarifies limits on external switches: "A single physical adapter can be bound to only one External virtual switch at a time (unless using NIC Teaming). Additional External switches require additional physical adapters." In the exhibit, Server1 has a single NIC already bound to vSwitch3, and the tree shows 'Microsoft Hyper-V Network Adapter', indicating the management OS shares the adapter. Therefore, you cannot add another External switch with the lone NIC; you can still create Internal and Private switches.
Regarding host connectivity, the guide specifies: "The management OS can communicate with VMs attached to an Internal switch and to an External switch (when the management OS is connected). The host cannot communicate with VMs on a Private switch." Consequently, Server1 can access network shares only from VMs on vSwitch2 (Internal) or vSwitch3 (External with management OS), but not from VMs on vSwitch1 (Private).