The Education Secretary said that it was extremely necessary that the…

Concept: In a statement-and-conclusion question, a conclusion is accepted only if it is consistent with, and reasonably follows from, what the statement itself says — without adding facts, audiences, or assumptions the statement never mentions. Where a statement asserts that two parties must act together for a task to be done properly, the best-supported conclusion is normally the one that explains the underlying reason for that necessity, while any conclusion that would make the stated arrangement pointless must be rejected.

Application: The Education Secretary calls it "extremely necessary" that professional researchers and practising school teachers conduct the practical research jointly. A conclusion claiming that teachers already possess full research expertise, or that researchers already fully grasp school-level problems, would each make the insistence on joint conduct pointless, so neither is consistent with the statement. The conclusion that fits without contradiction is the one that explains why joint, specialised effort is being insisted upon: school education is a specialised field, and without proper teacher training the standard of education cannot improve — this is precisely the reasoning behind treating the joint arrangement as necessary.

Cross-check: Restating the passage as "joint researcher-teacher work is insisted upon because school education is a specialised field requiring trained teachers" is consistent with the specialised-field-and-training conclusion and with no other option, confirming it as the best-supported inference.

Contrast with the other choices:

• Claiming that practising teachers already know research techniques is inconsistent with the statement — if that were true, insisting on bringing in professional researchers would serve no stated purpose.

• Claiming that professional researchers are already fully aware of school-education's practical problems is likewise inconsistent with the statement — if that were true, insisting on teacher involvement would serve no stated purpose.

• The statement gives no information at all about who the Education Secretary was addressing, so any claim about the audience goes beyond what is stated.