C is correct, and only C By the way, your question should not be about the article "the." Your question should be about the word 'grocery' and the use of 'are' and 'is.' Answer: Grocery is a plural noun, therefore it uses the plural verb are. Also, please refer to David's excellent explanation as well. Do you understand?

C. is correct. When using 'the' it can be used before singular or plural nouns. Groceries is almost exclusively plural because when you go to the store to buy groceries, you almost never buy just one thing. The only time I think I have ever heard 'grocery' is before the word 'store'. For example: I went to the grocery store to buy groceries. I hope that helps :D