Consider the integer A = 44444444. Let B denote the sum of the digits of A, let C denote the sum of the digits of B, and let D denote the sum of the digits of C. Find D. Here is a strategy for finding D: (a) Show that, for any integer N, N the sum of the digits of N (mod 9). Use this property to find the class of D mod 9. (b) Denote the number of digits of A by k. Estimate k and use this estimate to show that B 9k. (c) Repeat the previous step to estimate C and D. (d) In the previous step you should find that D is very small and knowing the class of A mod 9 should be sufficient to determine D