Jim Cramer answers viewers' Twitter questions from the floor of the New York Stock Exchange. As oil prices continue to decline, Cramer advises to stay away from National Oilwell Varco. He says the company is in one of the most perilous spots, which is big iron going into more drilling. He predicts the rig count to go down severely next year, as well as National Oilwell Varco's orders, which translate to its numbers declining and its stock falling. Plus, after what was expected to be a GoPro Christmas, Cramer acknowledges that the company faces challenges like a supply issue, but he is a fan of it long-term. Cramer also reveals his expectations for Apple's earnings and the stock in 2015.