A company is supposed to receive a data file every hour in an Amazon S3 bucket. An S3 event notification invokes an AWS Lambda function each time a file arrives...

A company is supposed to receive a data file every hour in an Amazon S3 bucket. An S3 event notification invokes an AWS Lambda function each time a file arrives. The function processes the data for use by an application.
The application team notices that sometimes the file does not arrive. The application team wants to receive a notification whenever the file does not arrive.
What is the MOST operationally efficient solution that meets these requirements?

A. Add an S3 Lifecycle rule on the S3 bucket with a scope that is limited to objects that were created in the last hour. Configure another S3 event notification to be invoked by the lifecycle transition when the number of objects transitioned is zero. Publish a message to an Amazon Simple Notification Service (Amazon SNS) topic to notify the application team. B. Configure another S3 event notification to invoke a Lambda function that posts a message to an Amazon Simple Queue Service (Amazon SQS) queue. Create an Amazon CloudWatch alarm to publish a message to an Amazon Simple Notification Service (Amazon SNS) topic to notify the application team when the ApproximateAgeOfOldestMessage metric of the queue is greater than 1 hour. C. Create an Amazon CloudWatch alarm to publish a message to an Amazon Simple Notification Service (Amazon SNS) topic to alert the application team when the Invocations metric of the Lambda function is zero for an hour. Configure the alarm to treat missing data as breaching. D. Create a new Lambda function to get the timestamp of the newest file in the S3 bucket. If the timestamp is more than 1 hour ago, publish a message to an Amazon Simple Notification Service (Amazon SNS) topic to notify the application team. Create an Amazon EventBridge (Amazon CloudWatch Events) rule to invoke the new function hourly.