The correct option is C 875
The largest possible number that can be formed from the given digits is definitely a three-digit number.
To find this number, we place the largest of 5, 7 and 8 in the place with the highest place value, which is the hundreds place.
That is, we place 8 in the hundreds place.
We then place the second largest digit (7) in the tens place.
Lastly, we place the smallest digit (5) in the ones place.
∴ The largest possible number from the digits 5, 7 and 8 is 875.