Where is this C# data type allocated

Each type in .Net is either value-type or reference-type. This is the most fundamental concept in .Net Common Type System. Memory for a value-type variable is allocated inline or on the stack (unless of course the value-type variable is a member of a reference-type object), and the reference-type variables are allocated on a heap managed by garbage collector. Here is an example code:

class Circle {
   public Circle(int rad) {
      radius = rad;
   }
   public double Area() {
       double pi = 3.142; // double is a primitive value-type.
       return pi*radius*radius;
   }
  // More methods here
   private int radius;  // int is also a primitive value-type.
}

class Test {
    struct AreaTestCase {
        Circle circle; 
        public void Run() {
            circle = new Circle(10);
            Console.WriteLine("Circle Area: {0}", circle.Area());
        }
    }

    static void Main() {
        var test_case  = new AreaTestCase();
        test_case.Run();
    }
}

Which one of followings is not true about above code?