A probe is written with no timing fields set. How long may each check take before it is treated as a failure?

Answer: A. 1 second

timeoutSeconds defaults to 1, alongside periodSeconds of 10, failureThreshold of 3 and initialDelaySeconds of 0 — an aggressive default that surprises slow health endpoints.

Source: Liveness, Readiness, and Startup Probes (Kubernetes) — Configure probes