What do signaling phrases in a research paper identify to a reader?

The author of a source
The type of source
The page number of a source
The publication date of a source

Couldn't it be either option a or c? I can only pick one, though. Please help? Thanks

4 answers

I vote for a.

http://www.capella.edu/interactivemedia/onlineWritingCenter/downloads/handoutSignalPhrases2009.pdf
Okay, I was feeling the same way. Thanks Ms. Sue:) (I'll let you know if that's correct...)
Yes, that was correct! Thanks again:)
You're welcome. And thanks.