【C#-題庫】函式與程序

出處：http://www.indiabix.com/c-sharp-programming/functions-and-subroutines/ 底下程式輸出為何？

namespace IndiabixConsoleApplication
{
    class SampleProgram
    {
        static void Main(string[] args)
        {
            int num = 1;
            funcv(num);
            Console.Write(num + ", ");
            funcr(ref num);
            Console.Write(num + ", ");
        }
        static void funcv(int num)
        {
            num = num + 10; Console.Write(num + ", ");
        }
        static void funcr (ref int num)
        {
            num = num + 10; Console.Write(num + ", ");
        }
    }
}

A. 1, 1, 1, 1, B. 11, 1, 11, 11, C. 11, 11, 11, 11, D. 11, 11, 21, 11, E. 11, 11, 21, 21,