Given statements:
1. All human beings need education.
2. All teachers need training.
3. Education is provided by the teachers.
4. X is a teacher.
5. X needs training.
6. Students are future of a nation.
The set of statements is:
We need the three statements that together read as one full argument, a general rule, a specific case, and the conclusion that must follow from them.
Only the rule-case-conclusion chain in 2, 4, 5 is complete, so the correct answer is 2, 4, 5.
Six statements are given, but only three of them combine into one valid inference; the other three, statements 1, 3, and 6, are distractors that never connect to the training-and-X idea. Let's check each option for how many of these distractors it drags in.
Since option C is the only one built entirely from 2, 4, and 5 with no distractor statement involved, the correct answer is 2, 4, 5.