Correct option is B
Coherence and Flow:
Introduction (C) sets the context by discussing the importance of a clean environment.
Elaboration (A) links environmental cleanliness with public health issues.
Accountability (B) emphasizes individual responsibility for maintaining cleanliness.
Conclusion (D) discusses possible reasons for neglect and suggests a solution.
Thus, the sequence CABD creates a logical and coherent flow, making option (b) the correct answer.