StorageGRID provides S3 bucket event notifications as a platform service that can inform external applications when specified object-level events occur. NetApp documentation confirms that event-notification destinations can be an Amazon SNS topic, Kafka topic, or webhook endpoint. Therefore, both the webhook endpoint in option B and the Apache Kafka endpoint in option C can notify the application when an s3:
ObjectCreated event occurs.
A webhook endpoint receives notification messages through HTTP POST requests and is appropriate when the application exposes an HTTP/HTTPS listener. A Kafka endpoint publishes the event to a configured Kafka topic, allowing an application or processing service to consume the event and immediately initiate object conversion. StorageGRID explicitly identifies sns, kafka, and webhook as supported notification endpoint types.
Option A is incorrect because a StorageGRID load balancer endpoint provides S3 client connectivity rather than bucket-event notification. Option D is also incorrect because CloudMirror replication copies objects to another S3 bucket; it is a replication service, not an application-notification mechanism.
Reference topics: Tenant Manager # Platform Services # Event Notifications # Kafka/Webhook Endpoints; S3 Bucket Notification Configuration