What is the most likely cause of the issue?

Universal containers (UC) has a mobile application that calls the salesforce REST API. In order to prevent users from having toenter their credentials everytime they use the app, UC has enabled the use of refresh Tokens as part of the salesforce connected App and updated their mobile app to take advantage of the refresh token. Even after enabling the refresh token, Users are stillcomplaining that they have to enter their credentials once a day .

What is the most likely cause of the issue?
A . The Oauth authorizations are being revoked by a nightly batch job.
B. The refresh token expiration policy is set incorrectly in salesforce
C. The app is requesting too many access Tokens in a 24-hour period
D. The users forget to check the box to remember their credentials.

Answer: B