can you explain this question

Q.1) When some values are changed in the current record (for example, when the user clicks on a button) and updates the database( by calling update method on the table buffer), How would you show the user the changes that have happened?

A.formDataSource.reread()
formDataSource.refresh()

B.formDataSource.research ()
formDataSource.executeQuery()

C.formDataSource.reread()
formDataSource.research()

D.formDataSource.refresh()
formDataSource.research()

any one can give me corect answer