Which of these joins does not require input topics to be sharing the same number of partitions?

In Kafka, every broker... (select three)

To prevent network-induced duplicates when producing to Kafka, I should use

is KSQL ANSI SQL compliant?

When is the onCompletion() method called?
private class ProducerCallback implements Callback {
@Override
public void onCompletion(RecordMetadata recordMetadata, Exception e) {
if (e != null) {
e.printStackTrace();
}
}
}
ProducerRecord<String, String> record =
new ProducerRecord<>("topic1", "key1", "value1");
producer.send(record, new ProducerCallback());