stuck with homework problem

Sort assumes that each of n input elements in array A is an integer in the range 0 to k, where k = 0(r). The array B holds the sorted output, and array C provides temporary working storage. Sort(A, B, k) let CIO.. k be a new array for i = 0 to k C[i] = 0 4for j- 1 to A.length for i= 1 to k 8 forj Alength downto 1 for j- A.length downto 1 C[i] = C[i] + Cli-1 1 10 Assuming Integer-Sort is correct, which of the three asymptotic statements, A, B, C or D describes its worst-case run time? A (n') nlgn C O(n) none of the above