Set a Budget Alert for Compute Engine Services

B.

The correct answer is A. Verify that you are the project billing administrator. Select the associated billing account and create a budget and alert for the appropriate project.

Here's why:

To set a budget alert for the use of Compute Engine services on one of the three Google Cloud Platform projects, you will need to have the appropriate permissions. In this case, you need to be the project billing administrator for the project in question.

Option A is correct because it specifically mentions verifying that you are the project billing administrator, which is the necessary permission level to create a budget and alert for a project's billing account. This option also indicates that you should create a budget and alert for the appropriate project.

Option B is incorrect because while it does mention creating a budget and a custom alert, it does not mention verifying that you are the project billing administrator, which is necessary to have the appropriate permissions to create the budget and alert.

Option C is incorrect because it only mentions creating a budget for the project, but not setting an alert. Additionally, being a project administrator is not sufficient to set a budget alert, as you need billing administrator permissions.

Option D is also incorrect for the same reasons as option B, as it does not mention verifying that you are the project billing administrator.

In summary, the correct answer is A, as it specifically mentions verifying that you are the project billing administrator and creating a budget and alert for the appropriate project.