All materials are purchased ex-tax because Dr. Magoo picks his materials up from a supplier in Nevada. On what measure does Mr. Magoo owe tax? Sale of prescription eyeglasses Sale of non-prescription sunglasses Repair parts for prescription glasses Prescriptions filled for eye surgeon Replacement of prescription contact lenses Totals Selling Price $ 450 250 100 150 200 $1.150 Cost Ex-Fax $250 150 50 100 50 $600