13.1 Two ways to create processing integrity controls in Excel spreadsheets are to use the built-in Data Validation tool or to write custom code with IF statements. What are the relative advantages and disadvantages of these two approaches? 13.2 Do you think the problem of hard-wiring in formulas in spreadsheets is still an issue? Why? In your formal instruction on Excel, were you taught not to hard-wire formulas? 13.3 For each of the three basic options for replacing IT infrastructure (cold sites, hot sites, and realtime mirroring), give an example of an organization that could use that approach as part of its DRP. Be prepared to defend your