I had no answer as I mentioned I am not in the Lab at Oracle analyzing why their software will do what it does. Its my job to determine what SQL is causing problems, then using the tools like ADDM, AWR, SQL Trace, & SQL Tuning Sessions to provide a direction for a potential fix. As far as the other options for the CBO, I would really hope most anyone is not using RULE these days because if they are, then I really dont want to work here. My answer did not go over well and pretty much imploded the rest of the interview, but I am honest and dont try to BS anyone.