Quiz: Initializing static fields correctly

A dev on the team recently found a bug in Whidbey a long these lines… Say you want to initialize the value of a static int to zero… which code should you use (C1 or C2) and, of course the most important point, why?

    class C1

    {

        private static int value = 0;

    }

    class C2

    {

        private static int value;

    }

BTW – I know these are not as tricky as some of my past ones… stay tuned, they will get harder ;-)