Problem Solving

Source: GMAT Paper Tests

For any sequence of n consecutive positive integers, Se denotes the sum of all even integers and So denotes the sum of all odd integers. Which of the following must be true?

I. There is at least one such sequence for which Se > So
II. There is at least one such sequence for which Se = So
III. There is at least one such sequence for which Se < So

A. I only
B. II only
C. III only
D. I and II only
E. I and III only

The OA is E