Below, a schedule is given for four transactions T1, T2, T3, and T4. Assume the initial values for the variables are A=5,B=10,C=15,D=0 Using a log with immediate updates, for each operation in each of the transactions, show: 1. The log entries. 2. Whether the write block buffer is updated. 3. Whether the DBMS on disk is updated. Discuss how each transaction recovers from the failure at step 18. A. What are the transactions that will do redo? B. What are the transactions that will do undo