Answer
C. Had a large base of support
edge
FALSE because "Sit!" is a sentence as when you instruct a dog to sit that is a whole sentence on its own.
I would say the correct answer is that has an undetermined answer.
If a subject has been thoroughly covered, then there is no need for this researcher to do it all over again. If it's impossible to answer, there is no need to try. If it can be answered easily, then it doesn't really require a research. This leaves us with the last option, because a researcher might want to try and determine the answer.
The correct answer is Harmonizer.
Why?
You have every person in the group (Apeers to be a music band), but you have no one to prudce it. This is why harmonizer is the correct answer.
Hope this helps!