Report Builder is the tool used to create reports, incorporate filters and select the Report Type. Data Loader is a tool used to import and export data in Salesforce. A csv file is a file format that can be used to import or export data in Salesforce, but it is not a tool to create reports. Report Composer is not a valid tool in Salesforce. References: https://help.salesforce.com/s/articleView?id=sf.reports_builder_overview.htm&type=5

Explanation
The business analyst should conduct individual interviews to gather input from the key stakeholders.
Interviews are a technique that involves asking open-ended questions to stakeholders or users to gather information and feedback about their needs, expectations, preferences, pain points, goals, etc. Interviews help to elicit requirements and user stories from the key stakeholders by allowing them to express their opinions and experiences in their own words, as well as clarifying any doubts or ambiguities. Interviews also help to avoid the influence or dominance of one stakeholder over others, as well as reduce the risk of groupthink or conformity. References:
https://trailhead.salesforce.com/content/learn/modules/salesforce-business-analyst-certification-prep/customer-di

Explanation
User stories are short descriptions of a feature or functionality from the perspective of an end user. They follow the format "As a <who>, I want <what>, so that <why>". The who is the user role or persona who will benefit from the feature or functionality. The what is the feature or functionality that the user wants or needs.
The why is the benefit or value that the user will get from the feature or functionality. User stories help translate requirements in a way that shows a product's value to the end user and helps prioritize and validate them. User stories do not provide specific details about a product early in the development lifecycle because they are usually high-level and flexible. User stories do not decrease the need for collaboration within a product team throughout the project because they require constant communication and feedback among stakeholders, developers, and testers. References: 1
https://parquet.dev/a-guide-to-salesforce-user-acceptance-testing/