What was the main industry in russia by 1900's

Which action bestillustrates the process of making an interpretation? a. a historian reads a secondary source about the cold war to find out the dates and locations of important historical occurrences. important historical occurrences, b. a historian publishes a popular article about racism in 20th- century south africa but does not cite any sources. c. a historian writes a textbook designed to teach college students about the duties of a professional historian. d. a historian reads speeches by english and french leaders during world war il to differentiate between their content and tone.