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? 

Answer options:

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.
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.
D. With the App Engine service account with delegated domain-wide authority.

B

Reference: https://developers.google.com/drive/api/v3/about-auth