Final answer:
In summation notation, if the lower bound exceeds the upper bound, the sum is always zero because no terms exist to sum within the given range.
Step-by-step explanation:
When the lower bound is higher than the upper bound in summation notation, the resultant value of the series is always zero. This is because there are no terms to add between the bounds, as the starting index is larger than the endpoint, which contradicts the usual method of stepping through the series incrementally. So, the correct answer to the student's question is (a) Zero.