单选题：Scala关于变量定义、赋值，错误的是？
Scala关于变量定义、赋值，错误的是？
A.val a = 3
B.val a:String = 3
C.var b:Int = 3 ; b = 6
D.var b = "Hello World!" ; b = "123"
答案：B
A.val a = 3
B.val a:String = 3
C.var b:Int = 3 ; b = 6
D.var b = "Hello World!" ; b = "123"
答案：B
