By Michael Pina Which team in the Eastern Conference will ultimately survive? Here are five storylines to follow as we enter the stretch run. View the original article to see embedded media. Depending on who you ask, somewhere between four and seven teams are built to win the Eastern Conference. Each is formidable in their own way, in a bracket that’s prime to yield the unexpected. And every realistic contender—from the Bucks to the Sixers to the Heat—has a serious question mark or two (or, if you’re the Nets, many more than that). As we sprint down the stretch, here are five variables that co…