Choice "D" is correct. The identification of critical applications will be found in almost all disaster recovery plans and thus is the best answer.Choice "b" is incorrect. Replacement of PCs could be in some disaster recovery plans, even though when it is, the plan is more likely to be called a business continuity plan. If end users cannot use their PCs because the PCs have been destroyed, they might not be able to access the recovered applications. However, PCs can be readily purchased, and many firms will decide to purchase replacements only when they need to (depending on the nature and extent of the disaster, the end users might be able to move to an alternate location which still has its PCs). However, that approach should probably be documented in the disaster recovery plan. Choice "D" is a better option.Choice "a" is incorrect. It is there to try to trick people into picking it because of the word "warehouse." After all, we do have "data warehouses."
Choice "c" is incorrect. Cross-training could be in some disaster recovery plans, assuming that the "operating personnel" means computer operations personnel (if it means something else, it won't be). Cross-training of computer operations personnel (anybody who will be expected to be at the disaster recovery site to provide the care and feeding of the applications) might be appropriate because the disaster might keep some of the expected people from being there. If so, then the cross-training should be documented in the disaster recovery plan. Replacement of personnel is something that is often incorrectly ignored in disaster recovery plans.