You have identified several problems that you need to track as the business analysis duties...

 Problem tracking is a document elicitation technique that can help in this scenario. Problem tracking is the process of identifying, documenting, and resolving issues that arise during the business analysis process. Problem tracking helps to ensure the quality and validity of the requirements and the solutions. Problem tracking also provides an opportunity for stakeholders to rank the importance of issues affecting them. Problem tracking can be done using various tools, such as spreadsheets, databases, or software applications. Problem tracking can help the business analyst to monitor the status of the issues, communicate the progress and outcomes to the stakeholders, and improve the business analysis performance and practices. The other options are not document elicitation techniques, but rather information elicitation techniques. Brainstorming is a technique that involves generating new ideas and finding solutions for a specific problem. Observation is a technique that involves watching how people perform their tasks or interact with a system. Interviews are a technique that involves asking questions and documenting the responses from a single person or a group of people. References:

Problem/Issue Tracking Technique — Business Analyst Learnings, paragraph 1

Elicitation Methods | SpringerLink, paragraph 1

Understanding the Document Analysis Technique - Business Analyst Learnings, paragraph 1