To answer this question, we need to understand how the "Dsname Level" works in the Data Set List Utility.
The "Dsname Level" is used to specify the high-level qualifier of the dataset that you want to list. In this case, we want to list all datasets with the high-level qualifier of the userid "ZTEST1".
Option A) ZTEST1 - This option is correct. By entering "ZTEST1" in the "Dsname Level" field, you are specifying the high-level qualifier as "ZTEST1", which will list all datasets with that high-level qualifier.
Option B) "ZTEST1" - This option is incorrect. The double quotes around "ZTEST1" are not necessary and will not work in the "Dsname Level" field.
Option C) .ZTEST1 - This option is incorrect. The asterisks (*) are used as wildcards in dataset names, but they should not be used in the "Dsname Level" field. They can be used to specify patterns for the dataset name, but not for the high-level qualifier.
Option D) 'ZTEST1*' - This option is incorrect. The single quotes around 'ZTEST1*' are not necessary and will not work in the "Dsname Level" field.
Therefore, the correct answer is A) ZTEST1.