Concept:Time zones are based on longitude. Without them, local time would not match the sun's position.
Explanation:Student 2 thinks seasons would change — irrelevant to time zones, so lowest clarity.
Student 3 believes all places have day and night together — wrong because opposite longitudes have opposite day/night.
Student 1 says longitudes would be useless — partially correct, but misses practical effect on daily time.
Student 4 correctly notes that morning would occur at different clock times — best understanding of the consequence.
Thus, increasing order of conceptual clarity is Student 2, then Student 3, then Student 1, then Student 4.
Answer:Option D:
2<3<1<4