As I stated in my explanation, (b) is 100% correct and (d) is 100% irrelevant.
Let me try to use an analogy to explain.
You own a book store. Book sales are down, but you notice that the gas station owned by your friend is making craaaazy profits, because the price of gas is so high due to an oil shortage. At the current price of $4 per gallon, your friend is making a lot of money. Accordingly, you decide to open up your own gas station.
How do the following 2 statements affect your chance of success:
(1) The biggest oil field in history was just discovered in India, which is immediately going to begin production and will undercut the sale of oil by other countries.
(2) People are unwilling to pay more than $4 per gallon of gas.
Well, (1) clearly presents a problem, since it makes us think that the price of gas is going to go down. (1) weakens your chance of success.
(2), however, is completely irrelevant. Your profits are based off the current price of $4 per gallon - it would be nice if people would pay more, but you'll be doing great at the current price. Therefore, (2) has no impact on your projection of profit at $4 per gallon.
(1) and (2) are basically the same as (b) and (d), respectively, in the question posted in this thread.