Jim Cramer tackles viewers' Twitter questions from the floor of the New York Stock Exchange. He weighs in on how Walmart is impacted from Dollar Tree buying Family Dollar, what he expects from Coach's quarterly results after the bell, and which of his four biotech horsemen he believes is best for a long portfolio. He also answers a viewer on what companies will benefit the most when Apple's new iPhone comes out -- the suppliers or the service providers. Lastly, he advises a recent college graduate on the number one stock he recommends investing in. Tweet your questions @jimcramer every Monday using #CramerQ.