When Making Reference in Your Paper to an Original Source

When making reference in your paper to an original source that you have not read but learned about it in a secondary source (such as a textbook) ,you should

A) not mention any source at all so as not to confuse the reader.
B) cite the secondary source in which you found the original source,and say,"as cited in..."
C) cite the original source of the information,not the source you read.
D) omit the information entirely until you read the original source.