Explanation/Reference: https://cloud.google.com/compute/docs/faq

The best options for reducing toil in the pipeline and minimizing the amount of time it takes to complete an end-to-end deployment are to create a trigger to notify the required team to complete the next step when manual intervention is required and to automate promotion approvals from the development environment to the test environment. A trigger is a resource that initiates a deployment when an event occurs, such as a code change, a schedule, or a manual request. You can create a trigger to notify the required team to complete the next step when manual intervention is required by using Cloud Build or Cloud Functions. This way, you can reduce the waiting time and human errors in the pipeline. A promotion approval is a process that allows you to approve or reject a deployment from one environment to another, such as from development to test. You can automate promotion approvals from the development environment to the test environment by using Google Cloud Deploy or Cloud Build. This way, you can speed up the deployment process and avoid manual steps.

The correct answer is B. Apply the constraints/iam.disableServiceAccountKeyCreation constraint to the organization.
According to the Google Cloud documentation, the constraints/iam.disableServiceAccountKeyCreation constraint is an organization policy constraint that prevents the creation of user-managed service account keys1.User-managed service account keys are long-lived credentials that can be downloaded as JSON or P12 files and used to authenticate as a service account2.These keys pose severe security risks if they are leaked, stolen, or misused by unauthorized entities34.By applying this constraint to the organization, you can completely eliminate the risks associated with the use of JSON service account keys and enforce a more secure alternative for authentication, such as Workload Identity or short-lived access tokens12. This also minimizes operational overhead by avoiding the need to manage, rotate, or revoke user-managed service account keys.
The other options are incorrect because they do not completely eliminate the risks associated with the use of JSON service account keys. Option A is incorrect because it only restricts the IAM permissions to create, list, get, delete, or sign service account keys, but it does not prevent existing keys from being used or leaked.
Option C is incorrect because it only disables the upload of user-managed service account keys, but it does not prevent the creation or download of such keys. Option D is incorrect because it only limits the IAM role that can create and manage service account keys, but it does not prevent the keys from being distributed or exposed to unauthorized entities.
Reference:
Disable user-managed service account key creation, Disable user-managed service account key creation.
Service accounts, User-managed service accounts.Help keep your Google Cloud service account keys safe, Help keep your Google Cloud service account keys safe.Stop Downloading Google Cloud ServiceAccount Keys!, Stop Downloading Google Cloud Service Account Keys! [Service Account Keys], Service Account Keys. [Disable user-managed service account key upload], Disable user-managed service account key upload.
[Granting roles to service accounts], Granting roles to service accounts.

Create log views for each project team, and only show each project team their application logs. Grant the operations team access to the _AllLogs View in the central logging project1.
This approach aligns with the Google Cloud's recommended methodologies for Professional Cloud DevOps Engineers1. Log views allow you to create and manage access control at a finer granularity for your logs. By creating a separate log view for each project team, you can ensure that they only have access to their respective logs. The operations team, on the other hand, can be granted access to the _AllLogs view in the central logging project, allowing them to view all logs as required.
This solution not only meets the security team's requirements but also minimizes costs as it leverages built-in features of Google Cloud's logging and does not require exporting logs to another service like BigQuery (as suggested in option A), which could incur additional costs1.