The cut-off marks can be different for different stages of the NABARD Grade A Exam (preliminary, mains, interview) due to the following reasons:

1. Different levels of difficulty: Each stage of the NABARD Grade A Exam (preliminary, mains, interview) is designed to assess different aspects of a candidate's knowledge and skills. The preliminary exam is generally the first stage and is conducted to screen a large number of candidates. It consists of multiple-choice questions and is relatively easier compared to the mains exam, which tests the candidates' in-depth knowledge of various subjects. The interview stage assesses the candidates' personality, communication skills, and suitability for the job. Therefore, the difficulty level of each stage can vary, which can result in different cut-off marks.

2. Number of vacancies: The cut-off marks may also vary depending on the number of vacancies available for each stage. If there are a limited number of vacancies, the competition among candidates will be high, and the cut-off marks are likely to be higher. Conversely, if there are more vacancies, the cut-off marks may be relatively lower.

3. Reservation policy: The cut-off marks for different stages of the NABARD Grade A Exam may also be influenced by the reservation policy. The authorities may have specific requirements for candidates belonging to different categories such as SC/ST/OBC/PwD. In order to ensure representation from all categories, separate cut-off marks may be set for each category.

4. Performance of candidates: Another factor that can influence the cut-off marks is the overall performance of the candidates in each stage. If the majority of candidates perform exceptionally well in a particular stage, the cut-off marks may be set higher to select the most deserving candidates. On the other hand, if the performance of candidates is below average, the cut-off marks may be set lower.

5. Normalization process: In some cases, when the exam is conducted in multiple shifts, a normalization process may be used to equate scores across different shifts. This process takes into account the difficulty level of each shift and ensures that candidates are not at a disadvantage due to variations in the difficulty level. As a result, the cut-off marks may vary for different shifts.

In conclusion, the cut-off marks for different stages of the NABARD Grade A Exam (preliminary, mains, interview) can be different due to factors such as the difficulty level of each stage, the number of vacancies, reservation policy, performance of candidates, and the normalization process (if applicable). It is important for candidates to prepare thoroughly for each stage and aim to score above the expected cut-off marks to increase their chances of qualifying for the next stage.