Show this document to them: https://www.uscis.gov/sites/default/files/document/forms/i-9instr.pdf
From page 5, Presenting Form I-9 Documents, Second Paragraph: "An employer cannot specify which document(s) you may present from the Lists of Acceptable Documents."
A few sentences later: "If you present acceptable List A documentation, you should not be asked to present, nor should you provide, List B and List C documentation."
On page 7 (instructions for the employer): "You cannot specify which document(s) an employee may present from these lists."