Q#1: Logical Reasoning (Strengthen)

A study found that students who use flashcards daily score higher on standardized tests than students who do not. The researchers conclude that using flashcards causes higher test scores.

Which of the following, if true, most strengthens the researchers’ conclusion?

A. Students who use flashcards also tend to study for longer periods overall.
B. Some students who do not use flashcards still perform well on tests.
C. The students who used flashcards were randomly selected from different schools.
D. Flashcards are commonly used in many different subjects.
E. Students reported that flashcards were easy to use.