下面的程序运行的结果是?public class Test {public static void main(String[] args) {int[][] arr = {{1,2,3},{4,5,6}};System.out.println(arr[1][1]);}}
A. 3
B. 4
C. 5
D. 6
请补充完善程序语句:定义一个数组来存储12个学生的成绩{72,89,65,58,87,91,53,82,71,93,76,68},计算并输出学生的平均成绩。public class Test {public static void main(String[] args) {int[] arr = { 72, 89, 65, 58, 87, 91, 53, 82, 71, 93, 76, 68 };double sum;sum = 0;for (int i = 0; i < arr.length; i++) {sum = sum + arr[i];}System.out.println("学生成绩的平均数是:" +);}}