What's your favorite rock group?
 Who's your favorite rock group?
 *Who're your favorite rock group?
Only  is given in the key to the task (to my great confusion). Just that  sound all OK to me, and while I try to follow the logic of  I start wondering why not  then? Which of  and  is more "grammatically correct', if I may say? Which is more appropriate in conversation? What's the difference? And whether  is possible too, say, in BE?
Thank you for your comments in advance.
I see now, so "who", same as "what", relates here to an inanimate group, not to its multiple animate members (musicians), and is meant singular.
What/who is your favorite singer/rock group?
Thank you for you help.
3 is possible in BrE.
It's "who is your favorite band?" A group of people are a "who" not a "what."
I wouldn't be surprised to hear "what" though.
Interestingly, google search gives the following results:
What / Who is your favorite band?
2.930.000 / 2.020.000 = 3/2
What / Who is your favourite band?
366.000 / 234.000 = 3/2
What / Who is your favorite singer?
3.020.000 / 971.000 = 3/1 (!)
What / Who is your favourite singer?
217.000 / 271.000 = 3/4
Last edited by trans; 16-Jun-2011 at 14:47.
Yes. Americans tend to consider groups to be singular. The band is touring Europe right now. Congress is in session. The committee is working on a proposal.
I just realized that I quoted preliminary search result numbers which diminish drastically when you reach last pages of the lists. I feel sorry for having possibly misguided you, here you are some smaller (and more consistent) numbers:
What is your favorite band? / What is your favourite band?
Who is your favorite band? / Who is your favourite band?
Who are your favorite band? / Who are your favourite band?
Thank you, Tdol, too!