Assume a database is being used simultaneously in two different sessions, as follows: Step Session 1 Session 2 CREATE TABLE X a VARCHAR(64), b INTEGER, PRIMARY KEY(a) CREATE TABLE Y (g VARCHAR(10)) START TRANSACTION READ WRITE, ISOLATION LEVEL READ COMMITTED INSERT INTO X (a, b) VALUES (Jeff, 10); COMMIT START TRANSACTION READ WRITE, ISOLATION LEVEL isolation level SELECT FROM Y START TRANSACTION READ WRITE, ISOLATION LEVEL READ COMMITTED UPDATE X SET b = 11 WHERE a 'Jeff' COMMIT 10 SELECT b FROM X WHERE a = 'Jeff START TRANSACTION READ WRITE, 12 13 14 ISOLATION LEVEL READ COMMITTED UPDATE X SET b = 12 WHERE a 'Jeff' COMMIT START TRANSACTION READ WRITE, ISOLATION LEVEL READ COMMITTED UPDATE X SET b = 13 WHERE a = 'Jeff' 15 16 17 SELECT b FROM X WHERE a = 'Jeff' COMMIT For each possible value for isolation_level in step 5 (READ UNCOMMITED, READ COMMITTED REPEATABLE READ, and SERIALIZABLE) . what value is returned by the query in step 16? And, describe why that value is returned. Assume a database is being used simultaneously in two different sessions, as follows: Step Session 1 Session 2 CREATE TABLE X a VARCHAR(64), b INTEGER, PRIMARY KEY(a) CREATE TABLE Y (g VARCHAR(10)) START TRANSACTION READ WRITE, ISOLATION LEVEL READ COMMITTED INSERT INTO X (a, b) VALUES (Jeff, 10); COMMIT START TRANSACTION READ WRITE, ISOLATION LEVEL isolation level SELECT FROM Y START TRANSACTION READ WRITE, ISOLATION LEVEL READ COMMITTED UPDATE X SET b = 11 WHERE a 'Jeff' COMMIT 10 SELECT b FROM X WHERE a = 'Jeff START TRANSACTION READ WRITE, 12 13 14 ISOLATION LEVEL READ COMMITTED UPDATE X SET b = 12 WHERE a 'Jeff' COMMIT START TRANSACTION READ WRITE, ISOLATION LEVEL READ COMMITTED UPDATE X SET b = 13 WHERE a = 'Jeff' 15 16 17 SELECT b FROM X WHERE a = 'Jeff' COMMIT For each possible value for isolation_level in step 5 (READ UNCOMMITED, READ COMMITTED REPEATABLE READ, and SERIALIZABLE) . what value is returned by the query in step 16? And, describe why that value is returned