在下列源代码文件Test.java中,哪个选项是正确的类定义
A.public class test{ public int x=0; public test(int x ) { this.x=x; } } B.public class Test { public int x=0; public Test(int x ) { this.x=x; } } C.public class Test extends T1 T2 { public int x=0; public Test(int x){ this.x=x; } } D.protected class Test extends T2 { public int x=0; public Test(int x) { this.x=x; } }