Concept:The singular countable noun “variety” needs a suitable article before its modifier.Explanation:The sentence describes a large collection of goods, so the phrase should be “an overwhelming variety of goods.”The word “overwhelming” starts with a vowel sound, which means the article “an” is required.The words “any,” “every,” and “each” do not fit naturally before “variety” in this context.Thus, the best choice is the article “an.”Answer:C. an