Good Ways to Learn About Differences Between Companies' Cultures Is

Good ways to learn about differences between companies' cultures is:

A) talk to people who work for the company now or have worked for the company in the past.
B) read what employees say on online social media sites such as Glassdoor.com.
C) read the company website, especially the mission, values, and ethics.
D) all of the above
E) none of the above