It's C, here is a reference: https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html#services-sqs-batchfailurereporting

To avoid reprocessing successfully processed messages in a failed batch, you can configure your event source mapping to make only the failed messages visible again. This is called a partial batch response. To turn on partial batch responses, specify ReportBatchItemFailures for the FunctionResponseTypes action when configuring your event source mapping. This lets your function return a partial success, which can help reduce the number of unnecessary retries on records. https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html#services-sqs-batchfailurereporting

answer C

https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html#services-sqs-batchfailurereporting

C is correct. We need ReportBatchItemFailures to return only failed items A: batch window is the interval process time B: batch size is the size of the job D: queue visibility timeout is about re-process

https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html#services-sqs-batchfailurereporting

Lambda process messages in batches. If one message in the batch fails the whole batch considered failed and all messages in the batch return to the queue. For example if batch has 10 messages and message 5 and 7 failed to get processed, all 10 messages will return to the queue. So, successfully processed messages can get processed again. Now to prevent this to happen you have two ways (used to be one) 1. Write your code in a way to identify processed messages and delete them manually from SQS. 2. Partial batch response that returns only the messages that were failed to be processed (supported since Dec 2021). References: https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html https://docs.aws.amazon.com/lambda/latest/dg/with-sqs.html#services-sqs-batchfailurereporting

C is correct.

B is correct