Difficulty: Easy
Correct Answer: All participants in the race are students.
Explanation:
Introduction / Context:
This item mixes set restriction (“only students”) with a subset receiving an invitation (all girl participants). We must pick the conclusion guaranteed by the premises and avoid adding unstated coverage to groups not mentioned explicitly.
Given Data / Assumptions:
Concept / Approach:
From I), every participant is a student. From II)–III), we know some invitees exist (the girl participants), but nothing is said about non-girl participants. So we can conclude “all participants are students,” but we cannot conclude “all participants are invited.”
Step-by-Step Solution:
Verification / Alternative check:
Construct a model where non-girl participants receive no invite; A fails but B remains true. Hence B is the unique necessary conclusion.
Why Other Options Are Wrong:
Common Pitfalls:
Confusing “only students can participate” with “only participants are students.” The former implies participant → student, not the converse.
Final Answer:
All participants in the race are students.
Discussion & Comments