Definition: In this task, you will be presented with a text, a pronoun from the text, and two candidate names. You should determine what the pronoun refers to and classify the answers into A, B, or Neither. A and B here are referring to option A and option B. Position of the pronoun in the text is showed within two "_"s.
Input: The composer conducted soloists Ursula Zollenkopf, Jeanne Deroubaix, Hugues Cu*nod, Richard Robinson, Charles Scharbach and Robert Oliver, the NDR Chor and the NDR Sinfonieorchester. Stravinsky dedicated the performance to Alessandro Piovesan, director of the Venice Biennale, who had recently died. The first Paris performance, on 14 November 1958, was disastrous. According to Stephen Walsh, Pierre Boulez failed to fulfil _his_ undertaking to obtain adequate performers, and those that he could obtain broke down several times. <sep>, Pronoun: his <sep>, A: Stephen Walsh <sep>, B: Pierre Boulez

B