Option 1: It improved the prestige of the cavalry.

This option suggests that maintaining twenty horses for every ten cavalrymen was done to enhance the prestige of the cavalry. However, there is no evidence or indication tying the number of horses to the prestige of the cavalry. Maintaining a certain number of horses does not necessarily reflect the prestige of the cavalry. Therefore, this option is not a valid reason for the expectation.

Option 2: By this method, the government managed to have more horses under their command without having to increase the salaries of mansabdars.

This option proposes that the government expected mansabdars to maintain twenty horses for every ten cavalrymen in order to increase the number of horses available to them, without having to increase the salaries of the mansabdars. This is a plausible explanation as it suggests a strategy to increase the availability of horses without incurring additional costs.

Option 3: For rest during marches and replacements in times of war.

This option suggests that each cavalryman would require rest during marches and replacements in times of war, and maintaining twenty horses per ten cavalrymen would ensure the availability of fresh horses. This is the correct answer as it highlights the practical reasons behind the expectation.

Option 4: Because the mortality rate of imported horses