What is the smallest seven-digit number that can be formed with the digits 3, 5, 9, 0, 6, 8, and 2 using each digit only once?

The correct option is C 20,35,689
Arrange the digits in the increasing order of their values.
0 < 2 < 3 < 5 < 6 < 8 < 9
Place the smallest digit at the largest place and arrange the remaining digits in an increasing order.
Watch out! 2,35,689 has only six digits since 0 has no value at the beginning of a number!
To form the smallest seven-digit number, place 0 in the second highest place.
Thus, the smallest seven-digit number that can be formed is 20,35,689.