A payment service provider company has a legacy application built on high throughput and resilient queueing system to send messages to the customers. The implementation relied on a manually-managed RabbitMQ cluster and consumers. The system was able to process a large load of messages within a reasonable delivery time. The cluster and consumers were both deployed on Amazon Elastic Compute Cloud (Amazon EC2) instances. However, when the messages in the queue piled up due to network failures on the customer side, the latency of the overall flow was affected, resulting in a breach of the service level agreement (SLA). The development team had to manually scale the queues to resolve the issue. Also, while doing manual upgrades on RabbitMQ and the hosting operating system, the company faced downtimes. The company is growing and has to maintain a strict delivery time SLA. The company is now looking for a serverless solution for its messaging queues. The queue functions of handling concurrency, message delays and retries, maintaining message order, secure delivery, and scalability are needed in the proposed solution architecture. Which of the following would you propose for a cost-effective solution for the requirement?