Here is a table with information about some students: Name StudentID 123456 Joe Smith Abby Jones 234567 Credits GPA. 3.2 24 3.6 220 And a ToDo list transaction based on Joe earning an A in a 4 credit class. Start transaction Add 4 credits to Joe Change Joe's GPA to 3.66 End transaction I A) Why are the actions not idempotent? What could go wrong if we crash midway through the list? B) Rewrite the todo list so that the actions are idempotent. Q6: Why might a database need to undo part of a transaction?