Digital marketing

Suppose you were conducting research on digital marketing, explain if each of the suggested websites would be appropriate for your research paper. Each explanation should be between 5 to 7 sentences in length.
1. https://blog.hubspot.com/marketing/what-is-digital-marketing
2. https://www.digitalmarketer.com/digital-marketing/
3. https://en.wikipedia.org/wiki/Digital_marketing
4.https://markets.businessinsider.com/news/stocks/the-future-of-digital-marketing-2019- technologies-changing-the-digital-marketing-ecosystem-1028819474