:unsure: another good question with bad answer choices unfortunately.

http://technet.microsoft.com/en-us/library/ms178560(SQL.90).aspx

says: "sp_update_jobschedule is provided for backward compatibility only" so it still works, just Microsoft in their infinite wisdom decided to change it along with a number of other low level plumbing items in SQL Server between 2000 and 2005. Seeing how many people selected sp_update_jobschedue looks like I'm not the only one who fell into the trap, and I try not to cheat when answering these questions, just go on the knowledge that's already in my head.