You are adding a public method named UpdateScore to a public class named ScoreCard.
The code region that updates the score field must meet the following requirements:
It must be accessed by only one thread at a time.
It must not be vulnerable to a deadlock situation.
You need to implement the UpdateScore() method.
What should you do?

A.
Option A

B.
Option B

C.
Option C

D.
Option D

Explanation:
http://blogs.msdn.com/b/bclteam/archive/2004/01/20/60719.aspx