I've created an embedded answers (Cloze) question type in which the participants have to complete a table, but not all cells in this table should have something written inside. Some correct answers, in this case, must be empty cells (if something is written, is a wrong answer). I have no idea how to write this in the format of the sub-question to validate an empty answer. Maybe somebody can help me with this.
This is a part of my table:
