Dear Guest,
I am sorry if I went a little further than intended; it was not clear from the question that it was in a multiple choice question. However, it is a legal issue which I felt was necessary to mention, given that this is a public forum and some make take answers to be complete and not consider the ramifications.
p.p. - This stands for the Latin «per pro» or «per procurationem». p.p. is used when someone signs a letter by authority or proxy because another person is not available.
Furher info at this link:
http://en.wikipedia.org/wiki/Abbreviation
Hope this helps,
Tim