定义类Countter并实例化如下： class Countter(name:String){ val a = 1 var b = "counter" } val counter = new Countter("computer") 下列操作正确的是？
选项：

A: counter.name = “cpu”
B: counter.b = “conter2”
C: counter.a = 2
D: counter.a = counter.b