Why are Rosencrantz and Guildenstern summoned to Elsinore?

1.) Claudius and Gertrude want them to find out what is wrong with Hamlet.
2.) Claudius and Gertrude want them to reunite Hamlet and Ophelia.
3.) Claudius and Gertrude want them to take Hamlet with them to Wittenburg.
4.) Claudius and Gertrude want them to kill Hamlet.