Take a look at D&C 77: 15
"Q. What is to be understood by the two witnesses, in the eleventh chapter of Revelation?
A. They are two prophets that are to be raised up to the Jewish nation in the last days, at the time of the restoration, and to prophesy to the Jews after they are gathered and have built the city of Jerusalem in the land of their fathers."
So two Prophets it is! Who those two prophets are would be pure speculation on my part.