在下列源代码文件Test.java中，正确定义类的代码是( )。

A、pblic 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; } }