Which two actions should you perform?

You are developing a mobile instant messaging app for a company.
The mobile app must meet the following requirements:
Support offline data sync.
Update the latest messages during normal sync cycles.
You need to implement Offline Data Sync.
Which two actions should you perform? Each correct answer presents part of the solution.
NOTE: Each correct selection is worth one point.
A. Retrieve records from Offline Data Sync on every call to the PullAsync method.
B. Retrieve records from Offline Data Sync using an Incremental Sync.
C. Push records to Offline Data Sync using an Incremental Sync.
D. Return the updatedAt column from the Mobile Service Backend and implement sorting by using the column.
E. Return the updatedAt column from the Mobile Service Backend and implement sorting by the message id.