Option (C). I think the option was "all those who are not good singers do not have a good voice." As I remember the other two options were presupposing that only people with good voice are good singers, which would be incorrect since the question does not give information about other people who are good singers.
I can't seem to recall what question you are talking about and I don't remember answering 'none of the above' to any question either :(
Could you please give a little more detail about the question?
For the average income question my answer was coming out to be A because if the average incomes of both the provinces increase then the average of the total income from both of them will increase which cannot happen. the total number of people will remain the same and wherever they go there incomes will remain the same too so total income is unchanged. For the tax question my tax multiplier was -4 so tax revenue decrease should be 20.
the answer i guess will be price level increases in proportion to money supply... flexible qtm says MV=PY and we assume that v and y are constant. Not sure though! :(