In a school there are 7 subjects in class Xth. Each subject is taught on seven…

Concept: In a constraint puzzle, a statement "correctly identifies" a stated fact only if the fact follows directly and necessarily from the given constraints — not merely if it could be true under one particular way of completing the schedule. The passage directly asserts that History, Geography and Chemistry occupy three consecutive days (in some unspecified order); this is a certainty. No other trio of subjects is asserted, or forced, to occupy three consecutive days by the given constraints.

Application: Comparing the three statements against what the passage actually establishes:

• Statement I — Chemistry, Geography, History: exactly the trio the passage directly places on three consecutive days, regardless of the exact order among them, so it is certainly true.

• Statement II — English, History, Chemistry: substitutes English for Geography. English is fixed on Sunday, but the passage never fixes where (which three calendar days) the History-Geography-Chemistry block itself falls, nor the internal order within it, so nothing forces English's day to be adjacent to two members of that block — this statement is not something the passage establishes.

• Statement III — English, History, Geography: substitutes English for Chemistry. As with Statement II, the passage never fixes where the block falls relative to Sunday, so nothing guarantees English is adjacent to two of its members — this statement is likewise not established.

Cross-check: If the question meant 'could possibly hold under some schedule' rather than 'is established by the passage,' several statements might qualify depending on arbitrary choices the passage never makes, leaving the question with no fixed answer. Since exactly one statement (I) is guaranteed true under every schedule consistent with the passage, while II and III are neither guaranteed nor ruled out, the passage-established, unique answer is Statement I.