Detailed Instructions: 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.
Q: He returned in 1978 as ma*tre de conf*rences to the University of Paris VII, where in 1981 he became professor extraordinarius (professeur de premi*re classe) and in 1991 professor ordinarius (professeur en classe exceptionelle). In 2012 he became professor emeritus. At the beginning of _his_ career Chenciner worked on differential topology and its applications to dynamical systems, following the pioneering efforts of Stephen Smale, and also worked on singularity theory. <sep>, Pronoun: his <sep>, A: Chenciner <sep>, B: Stephen Smale
A:
A