Four Subjects --- Psychology, Accounting, Arts and Zoology were taught in four…

Concept: In a data sufficiency problem, a set of statements is sufficient only when it pins the quantity asked for down to a single, unique value. If two different combinations of statements each independently fix the same unique value, both combinations count as sufficient, and the correct choice must name every combination that works.

Applying this to the four one-hour periods starting from 2:00 p.m.:

1. The four consecutive slots are 2-3 p.m., 3-4 p.m., 4-5 p.m. and 5-6 p.m.

2. Statement I: Arts ended at 4:00 p.m. (so Arts = 3-4 p.m.) and was preceded by Zoology (so Zoology = 2-3 p.m.). This leaves the 4-5 p.m. and 5-6 p.m. slots for Psychology and Accounting, in either order.

3. Combine I with II: Psychology is scheduled last (5-6 p.m.), so the only slot left, 4-5 p.m., must be Accounting.

4. Combine I with III (independently of II): Arts (3-4 p.m.) is immediately followed by Accounting, so Accounting occupies 4-5 p.m.

5. Both combinations - I with II, and I with III - independently fix Accounting at 4-5 p.m., so either pairing alone answers the question.

Cross-check: Statements II and III together, without I, still allow more than one valid ordering of Zoology, Arts and Accounting across the first three slots, so Accounting's start time cannot be pinned to one value from that pairing - confirming that only the two combinations built on Statement I are sufficient.

Result: Since 'I and II together' and 'I and III together' are each independently sufficient, and no other pairing works, the correct choice is the option that captures both.