Which operator must be placed in the underlined part to have the following result?

int[][] mat = {{0, 1, 2, 3}, {4, 5, 6, 7}, {3, 2, 1, 0}, {7, 6, 5, 4}};

for (int r = 0; r < mat.length; r++) { for (int c = 0; c _____ r ; c++) System.out.print(mat[r][c] + " "); System.out.println(); }

< output >

0 4 5 3 2 1 7 6 5 4