To answer this question, we need to understand the concepts of RESTORE, REPRO, and IMPORT in the context of data sets.
RESTORE, REPRO, and IMPORT are commands used in data processing to restore or recreate existing data sets. However, before using these commands to restore an existing data set, a DELETE/DEFINE command must be used to delete the existing data set and define a new one.
Let's go through each option to determine which one requires a DELETE/DEFINE before the command can be used to restore an existing data set:
Option A) REPRO only - This option is incorrect. The REPRO command alone does not require a DELETE/DEFINE before it can be used to restore an existing data set. The REPRO command is used to reproduce or recreate a data set from an existing data set.
Option B) IMPORT only - This option is incorrect. The IMPORT command alone does not require a DELETE/DEFINE before it can be used to restore an existing data set. The IMPORT command is used to import data from an external source into a data set.
Option C) Both REPRO and IMPORT - This option is incorrect. Although both the REPRO and IMPORT commands can be used to restore existing data sets, neither of them requires a DELETE/DEFINE before they can be used.
Option D) Neither REPRO nor IMPORT - This option is incorrect. Both the REPRO and IMPORT commands can be used to restore existing data sets, although they may not require a DELETE/DEFINE before they can be used.
The correct answer is option A) REPRO only. This option is incorrect because the REPRO command does not require a DELETE/DEFINE before it can be used to restore an existing data set.