Unique category-supplier pairs

The "Kotomarket" catalog stores products: each one has a category and a supplier. The same supplier can supply several products in the same category, so the table contains many repeated combinations. The purchasing manager needs a reference list: which unique category-supplier pairs occur in the catalog, with no duplicates. Return every unique combination of the category and supplier columns from the products table. Sort the result by category, then by supplier (ascending). Expected columns: category, supplier.