To understand what a disposition of (MOD,KEEP,) means, the user needs to know about dataset dispositions in mainframe systems.

A dataset disposition is a set of instructions that specifies what should happen to a dataset after a job completes. It can include options such as KEEP, CATLG, or DELETE, which determine whether a dataset should be retained or deleted and whether a catalog entry should be created.

In this case, the disposition of (MOD,KEEP,) means that the dataset should be opened for output in "modify" mode (MOD), which allows existing data to be updated or added to, and should be kept (KEEP) after the job completes, regardless of whether the job ends normally or abnormally.

Now, let's review each option and determine which one is correct:

A. Dataset is created if not available: This option is incorrect because the disposition of (MOD,KEEP,) assumes that the dataset already exists and is being modified. It does not involve creating a new dataset.

B. Dataset will deleted on abnormal termination: This option is incorrect because the disposition of (MOD,KEEP,) explicitly specifies that the dataset should be kept regardless of whether the job ends normally or abnormally.

C. Dataset will not be deleted on abnormal termination: This option is correct. The disposition of (MOD,KEEP,) specifies that the dataset should be kept after the job completes, even if the job ends abnormally.

D. job will abend if the data is not available: This option is incorrect because the disposition of (MOD,KEEP,) assumes that the dataset already exists and is being modified. It does not involve checking for the availability of the dataset.

Therefore, the correct answer is:

The Answer is: C. Dataset will not be deleted on abnormal termination.