Syllogism with a common subclass — decide what must be true Statements: • All terrorists are guilty. • All terrorists are criminals. Conclusions to evaluate: I. Either all criminals are guilty or all guilty are criminals. II. Some guilty persons are criminals. III. Generally criminals are guilty. IV. Crime and guilt go together.

Introduction / Context:
The premises say the set of terrorists sits inside both the set of guilty persons and the set of criminals. The question is which conclusions are logically compelled by this shared subclass. Beware of vague language such as generally or go together, which does not have a precise logical meaning.

Given Data / Assumptions:

• T = terrorists, G = guilty persons, C = criminals.
• T ⊆ G and T ⊆ C.
• It is standard to assume that T is nonempty in such tests.

Concept / Approach:
If a nonempty set T is contained in both G and C, then there exists at least one element that is simultaneously in G and C. That is enough to validate an existential conclusion connecting G and C. However, universal claims comparing all of G and all of C are not justified by the premises.

Step-by-Step Solution:

Verification / Alternative check:
Model: Let T = {x}. Let C = {x, c2} and G = {x, g2}. Premises hold. II is true since x ∈ C ∩ G. I, III, and IV are not forced because c2 may be outside G and g2 may be outside C.

Why Other Options Are Wrong:

• Only I follows / Only I and III follow / Only II and IV follow: each includes at least one conclusion not guaranteed by the premises.
• None of these: option C already captures the single valid conclusion.

Common Pitfalls:
Reading vague phrases as universals; assuming C ⊆ G or G ⊆ C without evidence.

Final Answer:
Only II follows