Identify the principle or rule of counting. Suppose that a procedure can be broken down into a sequence of two tasks. If there are n ways to do the first task and for each of these ways of doing the first task, there are m ways to do the second task, then there are nm ways to do the procedure. If a task can be done either in one of n ways or in one of m ways, where none of the set of n ways is the same as any of the set of m ways, then there are n+m ways to do the task. If a task can be done in either n ways or m ways, then the number of ways to do the task is n + m minus the number of ways to do the task that are common to the two different ways. If k is a positive integer and k + 1 or more objects are placed into k boxes, then there is at least one box containing two or more of the objects. A. The product rule B. Generalized pigeonhole principle C. Pigeonhole principle D. The sum rule E. Principle of inclusion-exclusion