A repository uses Copilot to prepare pull requests that may update application code. The validation workflow should run on pull requests into main, read repository contents, and comment only when the guardrail script detects a policy violation. The job should not receive repository write permissions beyond pull request comments. Which option completes the workflow?

The pullrequest event trigger (Missing value 1) is correct because the workflow needs to run specifically when a pull request is opened or updated, as stated in the requirement "run on pull requests into main." The pull-requests: write permission (Missing value 2) is necessary to allow the workflow to comment on the pull request, fulfilling the requirement to "comment only when the guardrail script detects a policy violation." The run keyword (Missing value 3) is used to execute shell commands directly within a step, such as the gh pr comment command for commenting on the pull request. Incorrect options: workflowdispatch would require manual triggering. issues permission is for managing issues, not pull request comments. push would trigger on pushes to the branch, not specifically pull requests. contents: write would grant excessive permissions beyond commenting. pullrequesttarget has security implications and is not needed here. actions permission is for managing GitHub Actions, not PR comments. uses, with, and env are not used for executing shell commands directly in this context.