Who do you think is the fourth apprentice in Warrior cats?

After reading book 6 of the third series I think it might be to do with Whitewings kits now that they have been born. They are still Firestars kin after all

OMG!! I just read the Warriors Sunrise book. [TOTALLY AMAZING] It was...WOW...I don't even know how to explain it!! But it was awesome..anywayyyyyy...... The fourth apprentice is DOVEKIT because she is on the FRONT OF THE FOURTH APPRENTICE! Ivykit has white with her TABBY fur! Icestorm i think the fourth apprentice is dovepaw