An event-driven architecture (EDA) is the most suitable pattern for systems that need to react to asynchronous occurrences. In this model, agents or services act as event consumers, subscribing to specific event types like 'ordercreated' or 'paymentfailed'. When an event occurs, a message is published to a broker, which then notifies the subscribed agents. This decouples the components and allows for a scalable, real-time response to business events as they happen, which is the core requirement of the scenario.

B. Manual spreadsheet updates are not an architectural pattern; this approach is slow, error-prone, and does not scale for real-time business processes.

C. Sequential offline batch processing is the opposite of real-time event handling; it processes data in scheduled, large chunks, introducing significant latency.

D. A script with no triggers cannot react to external events, making it fundamentally incapable of fulfilling the requirement to respond to business events.

1. Richards, M. (2015). Software Architecture Patterns. O'Reilly Media. Chapter 2: "Event-Driven Architecture". This chapter describes EDA as a pattern that promotes asynchronous communication and is ideal for systems that must respond to unpredictable events.

2. MIT OpenCourseWare. (2016). 6.033 Computer System Engineering, Spring 2018. Lecture 15: "Distributed Systems". The lecture discusses patterns for communication in distributed systems, highlighting the role of message queues and publish/subscribe models (foundations of EDA) for asynchronous operations.