单选题

public class a { &nbsppublic int num...

Question

public class a {
 public int num
 public int sum
 
 public a(){
  this(1)
  num++
 }
 
 public a(int num){
  this.num = num
  this.sum = num + 2
 }
}
public class testA {
 public static void main(String[] args) {
  a s = new a()
  System.out.println("num is" + s.num + "sum is" + s.sum)
 }
}

该程序的输出结果是（）

A. num is1sum is 3

B. num is2sum is 3

C. Num is2sum is 4

D. 都不对