Final answer:
The term referring to a junior or senior in college is 'Upperclassman,' which distinguishes them from underclassmen who are freshmen or sophomores.
Step-by-step explanation:
The term that refers specifically to a junior or senior in college is b) Upperclassman. This designation is used to differentiate the more advanced students typically in their third (junior) or fourth (senior) years of college, as opposed to underclassmen who are in their first (freshman) or second (sophomore) years. Understanding the classifications of college students is important in various aspects of college life, including academic policies and social stratification.