AWS Lambda is a serverless, event-driven compute service that perfectly aligns with the requirements. It is inherently highly available, as AWS manages the infrastructure and runs the code across multiple Availability Zones. The pricing model is pay-per-execution, making it cost-effective for applications that run infrequently and for short durations. Most importantly, Lambda abstracts away all server management, including patching, scaling, and provisioning, which results in the least possible operational overhead for the company. The developer only needs to focus on the application code.

A. Amazon EC2 requires manual provisioning, scaling, and management of virtual servers, including the operating system. This represents the highest operational overhead and is not cost-effective for infrequent workloads.
B. AWS Fargate is a serverless compute engine for containers, which has less overhead than EC2. However, it still requires building and managing container images and task definitions, which is more overhead than Lambda.
D. Amazon Aurora is a managed relational database service. It is used for data storage and retrieval, not for running application code, making it an incorrect service type for this requirement.

1. AWS Lambda Developer Guide: In the "What is AWS Lambda?" section

it states

"Lambda is a compute service that lets you run code without provisioning or managing servers... Lambda runs your code on a high-availability compute infrastructure and performs all of the administration of the compute resources...". This confirms its high availability and minimal operational overhead.

Source: AWS Lambda Developer Guide

"What is AWS Lambda?".

2. AWS Lambda Features: The official features page highlights

"With Lambda

you can run code for virtually any type of application or backend service - all with zero administration... Lambda takes care of everything required to run and scale your code with high availability."

Source: AWS Lambda official product page

"Features" section.

3. AWS Compute Services Overview: Comparing compute options

AWS documentation positions Lambda for event-driven applications where you want to eliminate server management entirely. In contrast

EC2 provides maximum control but also maximum operational responsibility. Fargate sits in between for containerized workloads.

Source: AWS Documentation

"Choosing an AWS compute service".

4. AWS Well-Architected Framework - Serverless Applications Lens: This whitepaper discusses the benefits of serverless architectures

stating

"Serverless architectures remove the need for you to provision and manage physical or virtual servers... This reduces the operational overhead required to run and manage your workloads."

Source: AWS Well-Architected Framework

"Serverless Applications Lens" whitepaper

Introduction section (p. 1).