Re:SC help needed!!

1. In the mid-1920's the Hawthorne Works of the Western Electric Company was the scene of an intensive series of experiments <<< that would investigate changes in working conditions as to their effects on workers' performance>>>.

D. that investigated changes in working conditions' effects on workers' performance

明瞭・簡潔

2. <<< Unlike their counterparts in other Western democracies, the American labor movement has never>>> embraced revolutionary ideologies calling for the ultimate transformation of the economic order.

B. Unlike that of their counterparts in other Western democracies, the American labor movement has never

「labor movement」を対比するためにUnlikeの後に”that”は必須ではないでしょうか？