Which method can be done to meet these requirements?

A mobile application developer intends to use Alibaba Cloud Object Storage Service (OSS) to store the end user data for their app, and to ensure data isolation between each user of the app, to prevent one user from obtaining another’s data.

Which method can be done to meet these requirements?
A . RAM Policy
B . STS authorization
C . Bucket Policy
D . Object Policy

Answer: B