I have to say example A sounds really forced to me. I would expect to hear "a special thank-you goes out to..."It is perhaps because the longer version is "I give you many congratulations." It is the same with "thanks" (the short form of "I give my thanks to you.") English almost always gives more than one "congratulation" or "thank".
It is possible to use the singular but it is rare:
A: "My thanks to the whole team for the effort that they put in this year, and a special thank goes to John who sold the most items."
B: "Stop it! This is not the time for congratulation, the job is not finished yet." (uncountable)
C: "I don't think that John likes Peter. Did you notice that when Peter won the prize, John gave a congratulation that seemed insincere?"