During the year that Spotify has been listed on Nasdaq, it has shown results such as: net sales of $ 5.259 Billion dollars and $ 3.906 Billion dollars in sales costs, resulting in a ratio of 74% of sales income and are represented as costs of them, among which are practically all the expenses generated by the sale of the streaming service, in this specific case, the expenses are not represented in a physical or tangible way as they can be in other activities. The previous news article published by Investing.com in 2019, what type of financial instrument does it refer to?

a) Corporate bond

b) Report

c) Initial public offering

d) Convertible preferred stock