1. In repousse, a method of sculpture, workers lay copper sheets over wooden molds, and then, using a variety of exotic hammers, carefully pounding the metal into shape.

(A) In repousse, a method of sculpture, workers lay copper sheets over wooden molds, and then, using a variety of exotic hammers, carefully pounding the metal into shape.

(B) Repousse is method of sculpture in which workers lay copper sheets over wooden molds and then, using a variety of exotic hammers, carefully pound the metal into shape.

(C) Repousse workers, who do a method of sculpture by laying copper sheets over wooden molds, use a variety of exotic hammers, and then pounding the metal into shape.

(D) Workers who lay copper sheets over wooden molds use a variety of exotic hammers and carefully pound the metal into shape in order to do repousse, a method of sculpture.（B）

(E) Laying copper sheets over wooden molds, and using a variety of exotic hammers in order to pound the metal into shape, repousse is a method of sculpture done by workers.

请问A错在什么地方?另外正确答案B中wihich从句前置的in是从句中的什么搭配?

thanks !!!!!!