The option that MOST effectively clarifies the similarities or differences in meaning between the terms "stretch" and "duration" is:
Both are referring to a time frame.
This option accurately captures the context in which both terms are used, emphasizing that they relate to periods of time, though with different connotations. "Duration" typically refers to the entire length of time something lasts, whereas “stretch,” in this context, suggests a potentially uncertain or challenging length of time.