Explanation
An ETL tool is an integration approach that the consultant should recommend to populate data from the SIS to Salesforce, and automatically modify the data to correspond to values in Salesforce. An ETL tool is a software application that can extract, transform, and load data from one system to another. An ETL tool can perform data transformations such as mapping, filtering, sorting, and aggregating, to ensure that the data from the SIS matches the values in Salesforce. Lightning Connect, Salesforce Data Import Wizard, and Salesforce Data Loader are not integration approaches that can automatically modify the data to correspond to values in Salesforce. References:
https://developer.salesforce.com/docs/atlas.en-us.integration_patterns_and_practices.meta/integration_patt
https://trailhead.salesforce.com/en/content/learn/modules/data-integration-strategies