In watsonx.data; what happens when multiple users submit queries simultaneously and the engine reaches its concurrency limit?

Resource groups in watsonx.data include queue settings; when an engine is at capacity; new queries wait in the resource group's queue rather than immediately failing; providing orderly backpressure. The incorrect options ("All new queries are immediately rejected with an error", "The engine automatically provisions additional worker nodes without any configuration", "Queries are converted to batch Spark jobs automatically") are distractors that don't fully capture the concept described.