The correct answer is Taints on nodes prevent pods without matching tolerations from being scheduled and tolerations permit pods to be placed on nodes that have those taints.

A taint applied to a node marks that node so the scheduler will not place pods that do not explicitly tolerate the taint. Taints are defined with a key and optional value and an effect such as NoSchedule, PreferNoSchedule, or NoExecute.

A pod toleration is a declaration in the pod spec that it can tolerate a taint. Tolerations do not force the scheduler to place a pod on a tainted node and they do not bypass other scheduling constraints. They only allow the pod to be considered for nodes that have matching taints.

The NoExecute effect will evict existing pods that do not tolerate the taint and it also prevents new pods without a matching toleration from being scheduled on that node.

Taints act like node label selectors and tolerations act like pod label selectors is incorrect because taints and tolerations are not label selectors. Node selectors and node affinity use labels to select nodes and that is a different mechanism than taints and tolerations.

Taints on nodes define resource limits and tolerations on pods declare resource requests is incorrect because resource requests and limits are defined in the pod spec resources section and taints do not set resource capacities or requests.

GKE node pools decide where pods run and tolerations only apply to node pool membership is incorrect because node pools are a provider grouping of nodes and do not replace taints and tolerations. Tolerations apply to taints on nodes regardless of node pool membership and you can use labels or node selectors to target specific pools.

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