The SYSIN DD statement in JCL provides control statements to utility programs like SORT. For SORT, SYSIN specifies: which fields to sort (SORT FIELDS), what format the data is in (e.g., CH, BI, PD), and what order to sort into (ascending/descending). Option D is incorrect because SYSIN does not specify the sort type - the utility program itself (SORT, MERGE) determines that.