CORRECT ANSWE R: D - Create separate tasks for ingestion, cleansing, and curation.

According to Microsoft Learn, Lakeflow Jobs (formerly Databricks Workflows) supports multi-task pipelines where each task encapsulates a single, well-defined step. The official documentation states that best practice is to decompose complex pipelines into discrete tasks --- ingestion, cleansing, and curation --- so that each task contains only the logic appropriate for that stage. This approach aligns with the Contoso planned change to 'implement scalable data pipeline orchestration' and the requirement to 'define a clear execution order and dependencies.' Option A is incorrect because combining all logic in one notebook violates the single-responsibility principle and makes retry/recovery difficult. Option B is incorrect because duplicating identical logic across tasks wastes resources and defeats the purpose of a modular pipeline. Option C is incorrect because a single SQL MERGE task cannot cleanly separate the ingestion, cleansing, and curation concerns required.