The correct approach is to assign the necessary roles (roles/bigquery.dataViewer and roles/bigquery.jobUser) to a group and then add users to this group. This method aligns with Google's best practices by utilizing predefined roles and managing access through groups, which simplifies permission management for multiple users with similar responsibilities. Creating custom roles (options B and D) is unnecessary when predefined roles meet the requirements. Directly assigning roles to individual users (option A) is less efficient and harder to manage than using groups.