For blue/green deployments in Kubernetes with Spinnaker, the best practice is to use Kubernetes Deployments. They offer declarative updates for Pods and ReplicaSets, support rolling updates, and align well with Spinnaker’s deployment strategies. Spinnaker’s Kubernetes V2 provider can manage multiple deployment objects for different app versions, facilitating traffic routing between them for blue/green deployments. Direct management of ReplicaSets is not recommended as they are typically controlled by Deployments. Creating new deployment objects for each version (Option D) is the correct strategy for blue/green deployments, whereas updating the existing deployment (Option A) is more akin to a rolling update. Options involving ReplicaSets (B and C) are not advised for deployment workflows.