Update README.md

README.md

@@ -82,7 +82,7 @@ An example from the TiLt-Pro dataset looks as follows:
 - `level`: The academic level of the tested knowledge. Can be one of the following: e.g. Middle School, High School, University Entrance, University, Professional etc.
 - `category_en`: The low level category according to the source IN ENGLISH, i.e. the exam name.
 - `category_original_lang`: Similarly to the `category_en` attribute, the low level category according to the source IN THE ORIGINAL LANGUAGE.
-- `original_question_num`: 
+- `original_question_num`: Id of the sample.
 - `question`: The text of the multi-choice question or the statement of the True-False question. 
 - `options`: A list of texts of the multiple choice options. In the case of True-False task, it is left blank.
 - `answer`: The string representing the correct choice(s) (1, 2, 3, ...). It corresponds to the numbering of the respective choice columns. In the case of True-False task, this is "1" for true and "0" for false.