Explanation:

Box 1: No
Zone2.contoso.com is not linked to any virtual networks. Therefore, no VMs are able to resolve names in the zone.
Box 2: Yes
VM4 is in VNet3. Zone1.contoso.com has a link to VNet3 and auto-registration is enabled on the link.
Box3: No
VNet3 is linked to zone1.contoso.com and auto-registration is enabled on the link. A virtual network can only have one registration zone. You can link zone2.contoso.com to VNet3 but you won't be able to enable auto- registration on the link.