The best answer for this question would be:
<span>Rosaline is the source of Romeo’s pain.
It adds a suspenseful mood, because the mere mention of Rosaline creates an awkward atmosphere for Romeo. This triggers a very hurtful past that Romeo has been through, and his friends understand that he must not become the man he was before. </span>
C.Benvolio.................................
When only two choices presented yet more exist, or a spectrum of possible choices in between.
