To answer this question, let's go through each option to understand why it is correct or incorrect:
Option A) The number of rows in the internal table - This option is correct. After a DESCRIBE TABLE statement, SY-TFILL will contain the number of rows in the internal table.
Option B) The current OCCURS value - This option is incorrect. The OCCURS value is used to define the number of occurrences of a structure or table type, and it is not related to the DESCRIBE TABLE statement.
Option C) Zero, if the table contains one or more rows - This option is incorrect. SY-TFILL will not contain zero if the table contains one or more rows. It will contain the number of rows in the internal table.
Option D) The length of the internal table row structure - This option is incorrect. The length of the internal table row structure is not stored in SY-TFILL.
The correct answer is A) The number of rows in the internal table. This option is correct because after a DESCRIBE TABLE statement, SY-TFILL will contain the number of rows in the internal table.