The correct answer is D. Exposed Bearer Tokens in Logs.

The scenario states that authentication artifacts associated with Kubernetes service accounts are appearing in logs or system-generated output. If those values can be reused to access cluster resources, they are functioning as bearer credentials. A bearer token grants access to whoever possesses it, so exposing it in logs creates a serious privilege-reuse risk.

Option A. No Certificate Revocation is incorrect because the weakness does not involve inability to revoke TLS or client certificates.

Option B. Unauthenticated HTTPS Connections is incorrect because the issue is not that HTTPS connections lack authentication. The issue is that valid authentication tokens are being logged.

Option C. No Non-repudiation is incorrect because non-repudiation concerns proving who performed an action. The scenario concerns credential exposure.

Option D. Exposed Bearer Tokens in Logs is correct because service-account bearer tokens recorded in logs could be reused by anyone who can access those logs.

Therefore, the best answer is D. Exposed Bearer Tokens in Logs.