B
Here is why i think it should be B
A)Challenging an assumption that certain desirable outcome can derive from only one set of circumstances - no mention anywhere
B)Challenging an assumption that certain desirable outcome is outweighed by negative aspects associated with producing that outcome.- As per the businessman the desirable outcome = Financial benefits to the locals- The Environmentalist proves his assumption wrong by stating that the pollution & noise is keeping the skiers away and this proves the assumption wrong- hence this can be correct
C) Maintaining that the benefit that the spokesperson desires could be achieved in greater degree by a different means- not relevant no mention anywhere , cannot be inferred from the para
d)Claiming that the spokesperson is deliberately misrepresenting the environmentalist’s position... - no reference in the para,again not a match
E)Denying that an effect that the spokesperson presents as having benefited a certain group of people actually benefited those people - it at all the Environmenatlist is stating it is not beneficial- due to noise pollution and no skiers which in a way will effect the business of local people.

so B comes closest to be the rght answer. it did take me 3,20 mins to guess this one..may not have got this one right under the time constraint