From I: All freshmen are human
From II: All students are human
From III: Some students think ⇒ therefore those students are humans who think.
Check each statement:
(1) All freshmen are students
→ NOT necessarily true. We only know freshmen ⊆ humans, students ⊆ humans. No link freshmen ⊆ students.
⇒ NOT a consequence.
(2) Some humans think
Since some students think and all students are humans ⇒ some humans think is TRUE.
⇒ CONSEQUENCE.
(3) No freshmen think
Nothing in the statements says freshmen do not think.
⇒ NOT a consequence.
(4) Some humans who think are not students
We only know some students think. We do NOT know that any thinker is outside students.
⇒ NOT a consequence.