A litigation researcher may start case law research with:

Starting case law research with various sources provides a comprehensive understanding of the legal context surrounding a particular issue. Secondary sources, such as legal encyclopedias, are especially valuable as they synthesize and summarize legal principles, helping researchers quickly grasp the relevant areas of law. They offer insights that can lead to more in-depth inquiries into primary case law.

Statutory comments often accompany statutes and can provide helpful interpretations or clarify legislative intent, bridging the gap between statutes and case law. While they may not be the primary starting point, they can still serve as useful references in the research process.

By integrating all these resources, a litigation researcher can effectively gather information, making option "D" the most comprehensive choice. Using a combination of secondary sources, statutory comments, and legal encyclopedias allows for a more well-rounded approach to understanding the applicable law, thus enhancing the researcher's ability to find pertinent case law efficiently.