-continued  112  US 8,852,845 B2  111  same as or different from every other substituent (Rb$_{2}$ )  and  also, the plurality of substituents (Rb$_{2}$ )  may combine with  each other to form a ring.  The repeating unit having a lactone group usually has an  optical isomer, but any optical isomer may be used. One  optical isomer may be used alone or a mixture of a plurality of  optical isomers may be used. In the case of mainly using one  optical isomer, the optical purity ( ee) thereof is preferably  90% or more, more preferably 95% or more.  Specific examples of the repeating unit (D) in the resin (P)  are set forth below, but the present invention is not limited  thereto. In the formulae, Rx represents  H, CH$_{3}$ ,  CH$_{2}$0H  or  CF$_{3}$ •  )j )j  0  0  0  0  clo  P  0  )j )j  0  0  0  0  ~o  ~  0  )j  0  0  Qt  0  0  LCl-17  LCl-16  LCl-15  0  LCl-13  LCl-12  LCl-11 