The correct option is A 99875
In order to form the largest 5 digit number, the leftmost digit at ten-thousands place will be the largest out of the 5 digits, that is, 9.
Since one digit can be repeated, we can either choose the repeating digit to be either of 9,8,7,5 or 4.
Since we want the largest possible number, we choose the repeating digit as '9'
Thus, digit at thousands place = 9
Similarly, we can say,
Digit at hundreds place = largest digit after 9 =8
Digit at tens' place = largest digit after 9 and 8 = 7
Digit at ones' place = largest digit after 9, 8 and 7 = 5
Placing the digits at their respective places we get 99875