Each of the digits in the number 7235491 is arranged in ascending order from left to right. What will be the sum of the digits that will remain unchanged as compared to that in the original number?

Original number: 7235491

Ascending order arrangement: 1, 2, 3, 4, 5, 7, 9

The sum of the digits that will remain unchanged as compared to that in the original number = 2 + 3 = 5

Thus, the correct option is (a) 5