Pages 1-9 will each have one digit.
Pages 10-99 will each have two digits.
Pages 100-366 will each have three digits.
There are 9 pages with one digit, 90 pages with two digits, and 267 pages with three digits each. So, the total number of digits = 1*9 + 2*90 + 3*267 = 990.
The correct answer is B.
hope this helps!! :)