Passage Summary: Old people were much better than college kids at remembering to make a phone call at a set time, suggesting that some memory skills stay sharp as we get older.

Conclusion: Aging does not necessarily lead to a decline in every single type of memory.

Reasoning: In a test of remembering to perform a task at a specific time, older adults significantly outperformed college students, with far fewer failures to complete the task.

Analysis: The argument wants to prove that aging isn't all downhill for the brain by showing seniors beating students at a specific memory task. Since we are looking for the 'least helpful' option, we want to identify which facts would strengthen the link between this specific result and the general conclusion about aging. Look for answers that rule out alternative explanations, like the students being busier or the seniors using external aids like calendars. The 'least helpful' answer will likely be irrelevant or even slightly undermine the comparison.