Assuming matrix[i][j] can be as large as k in the worst case, what is the time complexity of the above code?

public class VariableInnerLoop {
    public static void process(int[][] matrix) {
        for (int i = 0; i < matrix.length; i++){
            for (int j = 0; j < matrix[i].length; j++){
                for (int k = 0; k < matrix[i][j]; k++){
                    // constant operation
                    int dummy = k;
                }
            }
        }
    }
}