I recently purchased this very large and heavy octagonal sterling silver bowl from a thrift store for $400, which is the second most amount of money I've ever spent at a thrift store. I want to say its total weight is in the 2-3 pound range, so they sold it to me for silver melt cost.

On the bottom, it is stamped with what appears to be either an N or a D wrapped in a circle, sterling C4, as shown in the picture.

I cannot for the life of me and searching on the internet everywhere identify who the maker is based off of that image alone. Any help that you can give me would be much appreciated.