Which of the following are correct?

A. Primary source is a piece of evidence written or created during the period under investigation

B. Primary sources are the records of contemporaries who participated in, witnessed, or commented on the events one is studying

C. Primary sources, do not include newspapers

D. A secondary source is an account of the period in question written after the events have taken place

E. The distinction between primary and secondary sources is always very clear

Choose the correct answer from the options given below: