Answer: The hundreds digit.
Explanation:
This is because in the number 7889, there are both 8 in the tens and hundreds digit. And to get to the hundreds digit from tens digit we would have to multiply the current number in the tens digit by 10 to move it to the hundreds digit.
See the 8 in the tens digit, the number on the left of 9, as 80.
And see 8 in the hundreds digit, the number to the right of 7, as 800.
We would multiply 80 by 10, to get 800, and we see that the 8 has moved to the hundreds digit.
This is why the hundreds digit contains a digit where one digit is ten times the value as the other digit.