What is a primary source?

a.
a document made by someone who actually saw an event

b.
a photograph taken by a professional photographer

c.
a document created by someone who heard about an event

d.
a newspaper article about an actual person or event

What are your thoughts about " the attacking on the twin towers". in your own words a little paragraph its for a project i am doing and i want to get intel from other people so that i can put it on my poster. for anyone who gives me there opinion on it : ) enter you name when you type the paragraph more than one person to respond.