Explanation:

The `Mughal Mansab` system was a grading system used by the Mughal Empire to determine a Mansabdar`s rank and responsibilities.

1. The `Zat` rank was indeed an indicator of a Mansabdar`s position in the imperial hierarchy and was also used in determining the salary of the Mansabdar. This statement is correct.

2. The `Sawar` rank indicated the number of horsemen a Mansabdar was required to maintain. This was a direct reflection on his military responsibilities under the established Mughal hierarchy. This statement is also correct.

3. During the seventeenth century, Mansabdars who held a `Sawar` rank of 1000 or above were recognized as nobles, or `Umara.` This promotion further elevated their position and responsibilities in the imperial hierarchy. This statement is correct as well.

So, option 4, which suggests all statements 1, 2, and 3 are correct, is indeed the right answer.