You have configured a Compute Engine virtual machine instance as a NAT gateway. You execute the following command: gcloud compute routes create no-ip-internet-route \
--network custom-network1 \
--destination-range 0.0.0.0/0 \
--next-hop instance nat-gateway \
--next-hop instance-zone us-central1-a \
--tags no-ip --priority 800
You want existing instances to use the new NAT gateway.
Which command should you execute?

A. sudo sysctl -w net.ipv4.ip_forward=1 B. gcloud compute instances add-tags [existing-instance] --tags no-ip C. gcloud builds submit --config=cloudbuild.waml --substitutions=TAG_NAME=no-ip D. gcloud compute instances create example-instance --network custom-network1 \ --subnet subnet-us-central \ --no-address \ --zone us-central1-a \ --image-family debian-9 \ --image-project debian-cloud \ --tags no-ip