Explanation:

- To find the sum of all digits from 10 to 100, consider the two-digit numbers in each decade.

- Tens digit contributions:

- 10 to 19: \(1\) appears 10 times.

- 20 to 29: \(2\) appears 10 times.

- Continue this pattern up to 90 to 99.

- Units digit contributions:

- Each digit (0 to 9) appears 10 times for each complete set of ten numbers.

- Do not forget the number 100, which contributes one time for digits \(1\) and \(0\).

Calculate the sum:

- Tens place sum: \( 1*(10) + 2*(10) + 3*(10) + \ldots + 9*(10) = 450 \).

- Units place sum: Sum of 0 to 9 multiplied by 9 + 1 *(from 100) gives \( 45*9 + 1 = 406 \).

Adding both sums, the result is \( 450 + 406 = 856 \).

Option: 856 matches.

# 856