Option A is not the first step because the actual problem isn't yet identified. Option B is too narrow, focusing solely on the technical fix without considering the broader incident management process. Option C, while important, is a subsequent step after ensuring the application's stability. Option D is correct as it aligns with Google's recommended approach: first investigate the issue, and if it persists, appoint an incident commander to oversee the resolution process. Reference: Google SRE Book - Managing Incidents