Which of these methods allows the modification of a single document and returns the modified document?

The method that allows the modification of a single document and returns the modified document is findOneAndUpdate(). This method is specifically designed for situations where you want to update a document and simultaneously obtain the updated version of that document in a single operation.

When you use findOneAndUpdate(), you provide a query to find the document you want to update, specify the update operation, and can indicate whether you want the response to include the newly modified document. This is particularly useful for applications where you need to see the result of your change immediately after it’s made, without having to perform a separate query to retrieve the updated document.

Other methods, such as updateOne(), facilitate the update of documents but do not return the modified document itself. They only confirm whether the update operation was successful. The terms modifyDocument() and changeDocument() do not correspond to any standard MongoDB methods and are not recognized within the context of MongoDB operations. Therefore, findOneAndUpdate() stands out as the proper choice for both modifying and returning the updated document.