You Are Creating an App Engine Application That Writes a File

Multiple Choice

You are creating an App Engine application that writes a file to any user's Google Drive. How should the application authenticate to the Google Drive API?

A) With an OAuth Client ID that uses the https://www.googleapis.com/auth/drive.file scope to obtain an access token for each user. With an OAuth Client ID that uses the https://www.googleapis.com/auth/drive.file scope to obtain an access token for each user.
B) With an OAuth Client ID with delegated domain-wide authority.
C) With the App Engine service account and https://www.googleapis.com/auth/drive.file scope that generates a signed JWT. With the App Engine service account and scope that generates a signed JWT.
D) With the App Engine service account with delegated domain-wide authority.