The original numbers are: 135, 269, 667, 581, 783
Reversing the positions of digits within each number:
135 → 531
269 → 962
667 → 766
581 → 185
783 → 387
Arranging the reversed numbers in ascending order:
185, 387, 531, 766, 962
The second-largest number in this ascending arrangement is 766.
The last digit (unit place) of 766 is 6.
Therefore, the answer is Option 2: 6.