A primary source is written by the ones who participated in or observed the event.
So, out of the following, the three examples of a primary source are..
— A diary entry about the 1905 Revolution in Russia from a participant of the marches
— A speech given by a United States President
And, lastly,
— A Newspaper article from the day we entered WWI
I hope this helps, apologies if any of them are incorrect. Have a great day!