You recently deployed two network virtual appliances in us-central1. Your network appliances provide connectivity to your on-premises network, 10.0.0.0/8. You need to configure the routing for your Virtual Private Cloud (VPC). Your design must meet the following requirements: • All access to your on-premises network must go through the network virtual appliances. • Allow on-premises access in the event of a single network virtual appliance failure. • Both network virtual appliances must be used simultaneously. Which method should you use to accomplish this?