Top product you are given a list of product sales.

Question

I have encountered one problem statement recently. I am not sure answer about that question. I need answer for that. Can anybody explain in detail of that question and answer. Please suggest me.

I need answer in c#.

Please find the below link for the problem statement.
https://www.chegg.com/homework-help/questions-and-answers/top-product-given-list-product-sales-sale-consists-product-name-units-sold-next--upon-enco-q41518187#question-transcript