Countable Nouns

So I looked "brussels sprouts" up on wikipedia and the most interesting thing that wikipedia had to say about them is not that they are packed with vitamin C or a relative of the cabbage but that "brussels sprouts" is a countable noun, which I have never heard of but, of course, makes perfect sense. One can say "seven brussels sprouts" and be completely and utterly grammatically correct. (Okay, the real shocker for me here is that grammariticians need to dole out terms for every last thing - even things so obvious!) But anyhow, because I think it is humorous, my trivia question for the week is dealing in countable nouns.

Please, my friends, decide which of these is the countable noun:
a. milk
b. luggage
c. news
d. stereo
e. grass
f. grammar

And if it isn't weird enough that I was searching the internet for facts on (countable) brussels sprouts, I was also playing this game. Who knew that a vegetable could be good for so many laughs. And be such a perfect diversion for a girl who really should be working.