Final answer:
A changelog is crucial because it provides a detailed list of alterations to a spreadsheet or query, helping users understand project evolution and ensuring transparency.
Step-by-step explanation:
A changelog is important for tracking changes in a spreadsheet or query primarily for one key reason: c) To provide a specific list of important alterations. This document helps users and developers keep track of the various changes made to the spreadsheet or query, such as updates, bug fixes, and feature enhancements. By maintaining a detailed record, anyone reviewing the changelog can understand the evolution of the project, identify when specific changes were made, and ensure greater transparency and accountability within the development process.