Alibaba Cloud Certified Associate (ACA) Practice Test

In a microservice architecture, each request typically involves several distinct operations, each handled by a different service. A span is a single unit of work, representing a specific operation within that request's lifecycle. When a client makes a request that traverses multiple services, each service that processes some part of that request generates its own span. Additionally, the client initiating the request generates a span as well. Therefore, if the request goes through several services, the total span count includes one for the client and one for each service it interacts with. In this scenario, if there are four services in the path of the client request, this results in a total of five spans: one for the client and one for each of the four services. This sum is indicative of the distributed nature of microservices, where each service represents an isolated operation that contributes to the overall request's processing. Thus, the total number of spans is correctly determined to be five when incorporating both the client and the services involved in processing the request.