The correct logical sequence begins with D, which acts as a conversational link to a previous discussion, setting a contextual tone.
This is followed by B, which mentions the present conditions of racial and linguistic divisions, grounding the conversation in a current problem.
Then comes C, where the speaker reflects on the fundamental question of why such conflicts exist.
Finally, A generalises the concept of division to include gender, race, religion, and language, concluding the thought flow.
Thus, the most coherent sequence is DBCA.