Box 1: livenessProbe.
The correct answer is liveness because you want that your POD restart in case of failure.
Readiness remove the POD from Load Balancer, but doesn't restart it.
The kubelet uses liveness probes to know when to restart a container. For example, liveness probes could catch a deadlock, where an application is running, but unable to make progress. Restarting a container in such a state can help to make the application more available despite bugs.
The kubelet uses readiness probes to know when a container is ready to start accepting traffic. A Pod is considered ready when all of its containers are ready. One use of this signal is to control which Pods are used as backends for Services. When a Pod is not ready, it is removed from Service load balancers.
Box 2: periodSeconds: 15 -
The periodSeconds property designates the readiness command should execute every 15 seconds.