Need asap what is the main difference between primary and secondary sources? a: primary sources are historical documents, and secondary sources are modern-day documents. b: primary sources are derived from museums and archives, and secondary sources are created by history students and academics. c: primary sources are found in ancient places with a rich history, and secondary sources are found in historical journals and blogs. d: primary sources are created during a particular historical era, and secondary sources are created by studying primary sources.