To generate network latency reports for an API running across multiple cloud providers, two key steps are required: data collection and report generation.

• A. Use Zipkin collector to gather data: Zipkin is a distributed tracing system ideal for collecting latency data in multi-cloud environments. It is vendor-agnostic and specializes in timing data for latency analysis.
• C. Use Stackdriver Trace to generate reports: Stackdriver Trace (now Google Cloud Trace) is designed for latency analysis and can generate detailed reports. While it is part of Google Cloud, it can integrate with applications on other clouds if properly configured.

Fluentd (B) is for logging, not latency tracing. Stackdriver Debugger (D) and Profiler (E) are unrelated to network latency. Thus, A and C are the correct choices.