###Instruction: Multi-class classification, answer with one of the labels:['no_consensus', 'delete', 'keep', 'comment', 'merge', 'redirect'] : ###Input:  Q12951517: diffraction (Q12951517) : various phenomena that occur when a wave encounters an obstacle or a slit : ( delete | history | links | entity usage | logs ) Merged with Q133900 . Otourly ( talk ) 16:10, 29 July 2013 (UTC)